If you read the article it explains that bats and humans both have a structure called "false vocal folds" which can be used to make sounds as an alternative to the true vocal cords. These false vocal cords are what humans use to produce the growls in heavy metal (this has been known for a long time), and what bats use to vocalise (this has just been discovered).

Regarding your second point, if you think all research needs to be "for" something, then I can't help you.