Purpose of a music video

The Purpose of a music video is to;

• Sell the song. By making you remember the music.
• Give the narrative of the song a clear meaning.
• To be entertaining. It has to be entertaining or no one would watch it.
• To expand and expose the artists fan base.

In the end a music video is a promotional tool for the artist. Its all about CD or song downloads. The best way to get a hype about a song is to give it a massive video which gets everyone's attention.
There are certain genres that make their videos appeal more to their target audeince. e.g. rock have live performance,

Pop have male gaze, when the camera is in the view point of a man, for example focusing on bits that men like most about women.