Id say as someone who enjoys sleeping in the same bed (often with people who i am in a non-sexual relationship with and sometimes in a bed not designed for two people) it has kinda the same effect that cuddling with a person(sometimes it is just that) for a very long time so it just feels nice and has you rested in a completely different way. I do agree that the sleep quality often suffers a bit so i wouldn’t likely want to sleep like that every night.

It is kinda how many mammals have evolved to sleep, ever seen cats sleep in a big ball in weird positions over eachother?