I would like to know a bit more about the difference in sizing between a tub and a tank.

Pretty much all the forums I have read about BP husbandry is that you should be keeping an adult BP in a 20 gallon long tank.
Ok sounds reasonable.

On the other hand we have people who have racks. Now these tubs that they are kept in are 64quarts at the biggest. Which only equals to a 16 gallon space (not necessarily long).

My question is... is size of an enclosure really that big of a difference? Why do people seem so adamant about size but don't seem to notice rack tub sizes. (I do know they don't need height space since they are not arboreal).

My big girl is in her very own 20g long tank. I would eventually like to get more and was thinking of going the rack way eventually. I do not want to deprive her of space and would like to know personal opinions on the matter. What are the sizes of tubs you have? Sizes in racks aswell?

Thanks for reading my little rant/question lol