You can have the proper environment (and this includes temps, humidity, and hiding places) in a tub, a tank, AND a fancy cage! Period.

Tubs are not 'evil' or 'bad' for snakes. But neither are tanks. It can all work IF you put the right work and care into making them proper homes for a BP. The whole issue here, other than the 'feelings' thing which is moot, is aesthetics...and it shouldn't be an issue. Yes, it's nice to have a pretty cage with real plants and fancy hides, but most BPs just don't need or want that.
The most important thing to think of when readying a home for a BP, be it tub, tank, or cage, is getting it to hold the things that snake needs most - i.e. proper stable temperatures, the right level of humidity, and good secure hiding spots.

Now please... stop bashing each other and calling 'Tubs rule', or 'Tanks are the only way' and let's get back to some good snake keeping.