As major predators of insects, bats are beneficial and essential to the balance of nature. Bats are blind. Bats are rodents. Bats are the only flying mammal. Some species of bats are threatened.
Bats cause a high percentage of rabies cases.
Signals reflected back can also provide information on the type and size of a prey item. Humans can't hear many of the signals bats generate. The game of Marco Polo is a little bit like echolocation. The bat is blindfolded and has to locate each of its prey by sound. Investigate some of the legends about bats.