On the radio, your music speaks for itself. People hear your music and decide if they like it. No words were needed to describe it.
In concert, your music speaks for itself. Watching you perform, people appreciate your style as an artist. No words necessary.
But on the internet, and in print, and in conversation, words matter a LOT.
When people have not yet heard your music, your words describing your music have to be SO good that it makes people go to the trouble of hearing your music.
Online, the words need to make them go click the links to hear it (and buy it).
In print-media, the words need to make them put down the magazine and go find a way to hear you.
In conversation, the words need to make them remember enough to go hear you later.
It’s a BIG job, but since these are the ways you’re going to call attention to your music (until you’re on every radio/TV outlet in the world), you need to learn how to describe your music. It’s not that hard, and it’s VERY important.