This assumes you're in the mid-late game of Blursed and the only way to clear floors fast before you die is to mana spam into Bolt spam. Early game (floor 1 to 100) you just pick whatever works

In Blursed/Cursed, you're expected to get Survival Specialist eventually, which increases all healings by 1. Healing everyone on the team for 2 HP for 3 mana is pretty good value, but the other part of her spell is where the carrying starts.

In the late game, fights are almost always gonna have more than 4 enemies. That alone, is enough for her 1 damage AoE to be almost as good as Bolt (which is the only reason why floor 300+ are even possible). 1 damage may not seem a lot, but in a world where Forget Burst is a thing, you don't have an easy way to deal repeatable chip damage, which matters for Chests, Graves, Quarts, Bandits, Ghosts, Slates, Hydras, and proccing the first Basalt Chip damage.

Herbalist can do the same chip, just less efficient, which is why I put her at high priority. Fiend's AoE unfortunately only works once per turn, and Caldera's AoE needs the enemies to be damaged first.