My reasoning for this is that beds already serve as the closest thing to a 'pause' button in the game. They pause your hunger dropping besides just healing you. Unfortunately, if your planet has long (or especially cold) nights or days, than you can't put the character to bed and go to the bathroom without them freezing to death. Besides, it's just plain realistic. Beds are warm.
The idea is solid and would not mind if it was implemented just like that, but what about it applying differently to different beds? For example the Apex Torture bed wouldn't make sense to give off heat, neither would Floran Prison beds. But nicer beds could be extra warm.
The bed isn't warm, the fabric, blankets, quilts, etc help you retain your body heat and heat absorbed from other sources like your cat, dog, heater,etc but it's not natively warm. If you had a super warm bed with 20 blankets or quilts, if you're on a planet that's -50...you're going to freeze to death. If you can't survive the day or night on a planet then you need to think of ways to do so, be it torches, fireplaces, clothing,etc. I would suggest though that there be some high-tech beds that have built in heating units possibly? that would make sense at least.
That's kind of irrelevant to point out, because the way beds retain warmth is the same way that the current cold-weather clothes you can make keep you warm. I don't think it mentions having an internal heating system. I do like the idea of different beds working differently for different planets. Would be cool.
But this is exactly how thermal clothing works; it's not inherently warm it traps your body heat. I'd say being snuggled up in a bed is at least equivalent to 2 to 3 pieces of thermal clothing. Quod erat demonstrandum, it should counter all but the deepest cold.
Agreed. Certain beds should allow to maintain your heat. It doesn't make sense to have a nice cozy bed not be able to keep you warm at night.