He needs many mansions because when he gets mad at one (maybe it had a clogged toilet, or circuit breaker keeps tripping, maybe a leak in the roof), he burns it down, floods it, sends a plague of carpenter ants to turn it into sawdust, etc.
Yeah, he'll flood the place or zap it or something if his kids are naughty. Wait until you see those celestial tornadoes if one of his spirit children is gay.
When I was a TBM every time a temple got announced at General conference it made me very happy. God work is moving along more temple work can get done. Now I see it as such a waste of money. More work can get done to help the poor or homeless.
Because his followers are brainwashed into thinking that Heaven will be like earth where a few have everything and most have nothing. They, of course, will finally have the big house. And to think people like this idea. Jesus H. Christ.