You're looking at it from the point of view of a human. A BP wants to feel safe & secure and while some BPs do well in larger enclosures by no means do all do well in large spaces. In general a BP who roams during the day is considered to be stressed and most of the time making the space smaller or covered or quieter will cause them to calm back down.
They are ambush predators who spend 80-90% of their time hiding in the wild in spaces that many think of as being too small for them. They like the feeling of being secure in a dark, tight fitting space. Your opinions of space and freedom do not apply to this animal, only to you. If your biggest concern is providing the ideal environment for a BP then you should stop looking at it from a mammal's perspective.