It’s all about that action economy. Survive a terrasque hit (or hits in the case of multiattack)? No problem. Survive 8 terrasque hits? Problems.

So if you want your players to start RPing better (yikes that autocorrect) and playing more heroic people, you have the wrathful god spare them at the last moment or resurrect them with the threat of following through next time they meet if they don’t shape up? Or is this just a good way to wipe the board with a good ol’ TPK?