Brief summary of how arcane healing works.
When magical healing is mentioned in other articles, usually it makes the default assumption that we are talking about
Healing theurgy, a branch of divine magic.
Arcane mages can heal too. Just not as easily. If they are
arcane necromancers at least. Arcane Necromancers cannot mimic
Purification theurgy, but
arcane abjurers sort of can, though that's another story.
In game terms, a mage with Necromancy ●● can mimic the healing abilities of a theurgist with Healing ●. A mage with Necromancy ●●● can mimic the healing abilities of a theurgist with Healing ●●, and so forth and so on.
In narrative terms, the healing is
cosmetically different, but the end result are the same. The aura is a little different and arcane healing makes a very slight hissing sound. Divine magical healing feels pleasantly warm and arcane magical healing feels pleasantly cool, but the end result is the same. A sword wound healed by Healing ●●● is just as fixed as one healed by Necromancy ●●●●.
Tactical Implications necromantic healing
In general, about 60% of Scarterran mages choose to focus on two magic of magic, 30% choose to focus one school of magic and 10% choose to develop three or more schools of magic.
A disproportionately high number of necromancers choose to only focus on necromancy. Necromancers can get away with this more other mages can because Necromancy is more versatile.
Necromancers cannot summon minions as fast as Conjurers can or they can't hex people as efficiently as Enchanters can, nor can throw up defensives spells as well as Abjurers can, or smite foes as well as an invoker can, but Necromancy is a true jack-of-all-trades school. It can do a bit of everything.
Necromantic healing is the most poignant example of a piece of everything. Even Abjurers can't heal wounds after they are inflicted.
Opponents of a necromancer don't know exactly what to expect, and an arcane necromancer can play the role of a one-man army a lot better than any other lone mage.

Bendek by Eron12 on Hero Forge
"A scholarly mage that studied spell-craft from books will tell you that necromancy is the most versatile school of magic and that necromancers are true jack-of-all-trades casters. Being an arm chair general is nice and all, but you should talk to a mage who has been in the field.
Arcane necromancers are NOT unpredictable opponents. I've never seen a necromancer heal himself without a potion but I have seen every single one of them rely on Inflict Pain spells. Every. Single. One.
You need to be ready to dispel the pain effect or strongwill your way through it. Then hit them with a sword as quickly as possible not giving them time to retreat and heal up."
Sir Bendek Deorac, adventurer whose party leader drags him into fights with necromancers often
Economic Implications of necromantic healing
The most commonly sought after healing ability by soldiers and adventures is the ability to heal what in game terms is called "lethal damage", or in narrative terms is called "common battlefield wounds". This takes a theurgist Healing ●●● or a Necromancer ●●●●. It takes a necromancer more time and effort to reach this level than a healer theurgist. So there are more theurgists healers than arcane healers.
This costs a Healing theurgist three mana points or a Necromancer four quintessence points per casting. This means, that all factors kept equal, if a healer focuses entirely on healing as many people as possible, the theurgist will be able to heal 25% more people.
The above limitations aren't that big of deal to most. People who need magical healer generally know better than to look a gift horse in the mouth. If after a big battle, a theurgist heals 12 people and a necromancer heals 9 people, the army commander is just happy that 21 people were healed. If you don't have a healing theurgist around, 9 people healed is a lot better than zero.
But potions and other
Finite use magical items get exponentially more expensive the more advance the magic involved is. A common healing potion generally sells for 65 silver pieces when made by a theurgist, or 50 silver pieces if they sell it at cost.
A necromancer trying to make the same potion will expend at least 100 silver pieces of materials to make an identical potion and they will have a greater chance of accidentally making a misstep in the potion brewing process and accidentally ruining the ingredients for no gain.

by Eron12 with Heroforge
The cost of making a necromantic healing potion is so prohibitive, that no one will opt to buy a healing potion from a necromancer unless they have no other choice. Many necromancers don't even both to learn how to brew potions at all. I can making potions of varying types, but even then it costs me less money to buy a healing potion from a theurgist even with the markup though I normally have to wear normal peasant clothes when going potion shopping.
A few of my weaker colleagues are twisted in body and mind and cannot interact with normal society. These necromancers can't simply walk into a temple and buy a potion, so they are generally forced to make their own healing potions or make due without them."
-Magnati, freelance necromancer
Social Implications
Theurgists are all around better healers than necromancers, but the demand for magical healing exceeds the supply, so a necromancer can often win friends (or win begrudging acceptance) by offering healing services.
"Unless undercover, most mages like to dress loudly and flamboyantly. They will usually wear clothes and accessories that scream 'I'm a mage!'. We necromancers are a lot more likely to dress down than their arcane peers as we have something a public relations problem.
Necromancy can do a lot of benevolent. Vermin Purge can remove fleas and mice from an inn without harming any mortals though you might want to move your dogs and cats out of the building while the necromancers are doing work...just in case.
The spell "Repose" can restore dignity to the dead for delayed funerals. The spell "Name the Corpse" can positively identify a dead body and bring closure to the deceased loved ones. Even an pain inflicting spell can be a source for good because it can end a fight without bloodshed.
The problem is that necromancers are best known for creating undead or binding ghosts. The mere possibility that a necromancer might do these things gets normal people spooked.
In a lot of cases, the fact that we can serve as healers is the only reason why aren't automatically run out of town and it's a good selling point when trying to recruit talented apprentices."
-Dallas, necromancer of the Barony of Eternity
I didnt know necromancy was that versitile. the ore ya know...