What was the whole point of initially giving Joey an alcove?

Within the universe of the show, it's explained in about the first half of Season 1, that Joey is given the alcove under the stairs because there was no room in the house. Later, it was decided to turn the garage into a full room for him. Basically, why couldn't the writers simply say that Danny had a spare room for him right from the start? Didn't it feel like with the alcove concept, there was supposed to be some sort of joke that never exactly landed the way that the writers had hoped for.