No 1 He's a dog, not a human ! What's 'big and comfy' to him may not be as appealing now as the settee. Perhaps the settee is a bit firmer, perhaps it's in a cooler or quieter, less busy, part of the room , perhaps it has a smell which he finds more comforting, it's impossible to say.
No 2 Is easier. He's a dog, not a human ! He likes to feel that he is in his own tiny 'cave' Young dogs in particular love to be in a space which is close in on them They feel much more secure in a 'tight spot' They like cooler temperatures than we do, too. One of mine goes out into the yard at and sleeps cramped up in a tight space, on a board, in an old coal shed there. That's absurd, in human terms, because she has a choice of two dog beds and a mattress inside but no, it's through the dogflap and to the shed for her !.