If you're concerned about rabies, you need to be more cautious of your pet that hasn't had its annual rabies shot or that 'friendly' raccoon that visits your porch each night. Now that I've hopefully convinced you that bats aren't ghouls or demons, let me discuss the benefits of bats. The most direct contribution is their impact as natural pest controls. So, if you're lucky enough to have bats in your neighborhood or attic, try to encourage them to stay by not disturbing them. That way, you won't have to buy a bug zapper.
Bats have many indirect benefits.
In other parts of the world, some bat species eat fruit and disperse seeds, or drink nectar and pollinate flowers, like bees. The fruit eaters are called frugivores and typically pick a fruit from a tree but fly to a safe roost to consume it. In the process, they distribute the seeds throughout the forest resulting in new seedlings. Many flowers bloom only at night and rely on bats to transport their pollen from one flower to another. They entice the bats by rewarding them with plenty of nectar.