BP's in the wild live solitary lives in termite mounds and abandoned rodent dens, they will lay next to an opening when they are hungry and wait for some prey to walk by.
It is possible to keep them in a larger enclosure you will need to fill up some of the open space with plant and rocks, but there are other problems with a bigger enclosure than that. Its harder to control heat and humidity.
Also why would you want to take up more room than you need to? Tanks are big they take up a lot of room and if I had one for a bp I wouldnt go bigger than a 20g long.