... Asking for a Devil's Bargain seems to me like it increases the player's sense of these things, and hence their cognitive and emotional proximity to their character.
Hence why I deny the claim that Devil's Bargain-type mechanics are, in general and necessarily, inimical to immersion.
Wait a second. You increase the emotional proximity of the player to the character, and that is inimical to immersion?
How is being closer to the character's emotional state working against immersion into that character?