Movie Making Manual/Why Make a Music Video

There are several reasons why it is a good idea to make a music video.

For the Band:

To give your band exposure- a music video is one of the best ways to publicize a band, as it would no doubt be passed on by many people. The music video is not limited geographically, through the internet many people from around the world can view it. The music video does not cost in time, as once it is made the band does not have to perform again for every single audience.
To convey your visual style, giving people an incentive to see you perform live.
Experience- Performing in a music video gives the band/singer experience in performing elaborate and complex moves in exact sequence. While performing on a music video the band/singer doesn't have to perform live, and they/he can get feedback from the fans on how well they perform. The singer/band can then later repeat the moves they did on the music video on stage live, knowing exactly what moves the audience would love.

For the Crew:

To get experience in moviemaking, that may be useful before you try making a feature film. Music videos are a way of exploring visuals and styles in an abstract or surreal way without being confined by narrative restrictions. True expression can be found in these visuals, instead of trying to get a message across through actors and dialogue in a scripted environment.

As a Director, a music video can be the perfect outlet to freely express a creative style with some guided direction from the genre of the music. However it's important to note that freedom of expression for the Director can only be achieved if the performing artist approves of the content or Director buys the rights to the song.

It is short

By being a short video it can also be highly inexpensive in comparison to a feature or any other short based on what you do.