I mean, it still provides allies with some extra health.
But yeah, it's kind of underwhelming compared to other Bard subclass bonuses.
Glamour Bard feels like it's sort of in the same boat as Wild Magic Barb.
Where it can be pretty nice early game. But kind of falls off by the end of Act 1.
WM Barb has this by its WM procs can be pretty nice early on. But as they don't scale at all they quickly fall off as Extra Attacks and Cantrip Dice kick in.
While Glamour Bard can be decent throwing around that Temp Health (Especially with the early supportive Bard equipment that provides extra healing). which is meaningful early on and you won't have the tools to overwhelm many early encounters so you can proc some charms (Especially places like the Goblin Camp and the Creche). But as you get access to more power and health, it becomes less relevant.
