The player should not have to wonder whether to keep the character in the party or have additional food if he does not plan to use it, but only learn the story.
This is a silly system and goes against how most role-playing games work.
This is not a survival game and should never be.
I certainly don't want different rest costs depending on the difficulty level.
On a higher level, I wants stronger enemies with better stats and skills, and if possible, I wants them to be smarter. I don't want to increase the difficulty level by food problems.
