Act 1 mercs are also nice for melee range builds because they soften/kill cowardly ranged enemies while surviving better than most with a player char that tanks for them and teleports often. Just generally speed things up by helping with the most annoying enemy type to the playstyle. I do feel priestess AI is a little more efficient myself regardless of buffs between them, but that could just be placebo.
Miasma spam is a beautiful alternative as well of course.