At the same time we've got to point out that bats are wild animals. Additionally, most local jurisdictions, such as Washington, Oregon and California have laws prohibiting the capture and restraint of wildlife, such as bats. A bat kept as a pet is likely to die under your care. Eventrained wildlife rehabilitators have a steep curve as they learn to care for bats.
Bats have very high metabolic demands because they are very active and small.
That means a lot of insects. It also means lots of bat droppings. Good for fertilizer, bad for the typical home. Second, bats are very delicate creatures. The bones which enable a bat to fly are so fine and light, your bat could suffer from a broken bone within a short time in captivity.