you said the good reasons yourself. it's easy to heat and keep the humidity right. as far as having space to move around goes just buy a large enough tub to where he is satisfied with the amount of space that the snake will have. check out some of the larger ones on www.reptiletubs.com. you could always try to talk him into a boaphile or animal plastics cage. you will get the space he wants and the ease for you. then you would have the excuse that they look pretty darn nice.