Here is an illustration of a Betta's habitat and the reason why the pet industry profits from the misconception that Bettas enjoy small spaces.
It is still common to hear that tiny tanks replicate a Betta's habitat. This is because Bettas can *sometimes* get stuck in puddles during the dry season but they will avoid this and jump to bigger bodies of water when possible. It is a short-term and often uncomfortable situation for the Betta.
The tiny Betta cubes and fish bowls are misleading consumers into viewing them as appropriate long-term living situations for Bettas. These tanks only meet the bare minimum of keeping a fish alive. The pet industry has a responsibility to teach consumers proper Betta care!