Healing, eh? Well: An angel gets the full angel kit- not just 6-stock worth of healy goodness, but also all the assorted stuff that *doesn't* get used up to heal- stethoscopes, sensors, thermometers and what have you. If a first aid kit has, at most, 2-stock and can be carried around in a backpack with room for more but an angel kit can (probably barely) fit in the trunk of a car, I'm guessing there's a LOT of extra stuff in that angel kit.
What good is the angel if you can just restock the first aid kit? Well, for one the angel is probably better at using it, not to mention using it under fire. The angel can also try to just straight-up heal harm instantly, although it's kind of weird. Most of the angel's moves help them with that, while a gunlugger gets the kit as only one option among many, most of which would probably be more help at doing what the gunlugger does best.
What good is the angel or the angel kit if the quarantine can just heal what ails you in their neato-keen medlab, like a savvyhead and their workspace? Ever actually asked a savvyhead to fix you up? *shudders* You'll come out OK, but you'll often wish you had just asked somebody to fix you up the normal way instead. Less complications and often just plain cheaper.