This defines what gender or groups that could sing this song.
1. Artists and music publishers can use this when searching for the perfect song.
2. Fans can use this in their searches. Imagine a young girl in the mood to hear some powerful ballads that she can sing along with. She could do a search that included songs sung by a female that are about love and pain and at a BPM between 80 and 90. A search like this would return a list of songs like Adele's "Hello"....and she could sing her heart out!