******Please feel free to let me know if this is a stupid idea, or not worth the time and money******

For some reason I'm stuck on the idea of buying one of the Exo Terra nano habitats, probably the 8x8x12.
My questions and concerns are as follows

A) what kind of animal, frog or otherwise, can comfortably live and be healthy in such a small habitat.
Also, I would prefer to keep a pair in the nano if possible.

B) what are the drawbacks to such a small habitat?

Thanks for the help