At present, only the first health bar causes the “death” state to occur when it reaches zero. If I’ve got another bar and I take it down to zero, the character icon is unaffected. It would be nice if all health bars could be set to cause the “death” state or not, based on a preference on each health bar. (In principle, there are many things that could be tracked with one of these health bars that wouldn’t cause death when they reach zero, and there may be multiple different things that could be tracked that could all cause death if any one of them reached zero.)
I like that, especially when creatures cause Con or Strength drain that can result in a character’s death.
You could have a parameter that applies a condition effect at different levels. If a creature was affected by sickening radiance for example, a nice feature would be to automatically apply points of exhaustion and eventually death when they reach 6 levels.
I can also see a use for this. A health bar could also represent a more esoteric resource like levels in some games, and in such adventures undead sometimes get energy drain, causing permanent loss of levels until cured with something like restoration. If your level drops to zero or less, you’re dead.