It's all about the type of housing the snake does best in. Being the way they are, as was said, BPs like smaller, darker enclosures than most other species. Whereas there are exceptions (quite a few of my snakes prefer the head room of the tanks and the 12" tall tubs I use in my rack), most BPs like the 'cozyness' of the basic tub.

Because I spoil my snakes (), I give them the largest enclosures I can...and that includes tubs. But, when I find that someone doesn't like that room I give them the lower, smaller space.