I deliberately tried to keep the game output more narratively focused rather than directly explaining mechanics to the player, relying on "common sense" for decision-making. But I might as well clarify some things here for those like you who are more mechanically-focused.
Negative status effects like bruised, stressed, agitated, etc. do contribute to the overall risk of dying. Some are worse than others, but it's impossible to die exclusively of dysentery (for example). The death message attributes the death to the "worst" affliction available currently, but maintaining general health is important. So waiting to eat/sleep/warm up until you're starving/exhausted/hypothermic makes you vulnerable to dying if you then also get dysentery or a broken leg, which wouldn't happen if you were otherwise healthy.
But you're right that the bible and doppelganger event are mostly just for flavour, and it's not well balanced for variety over multiple playthroughs because I never really expected it to be played more than, like, twice.