SE probably thought that players would actually go out of their way to gather essences, lost actions, and the like (Valor) to not be a hindrance to their party. Unfortunately, many players would rather waste their own and other's time instead of doing so. Even if essences or lost actions were permanent (no usage limits) I suspect many would STILL not use them, and even if they were automatically applied, I bet people would go out of their way not to unlock them if they didn't have to, to complete the content.