he pros are telling the story behind the song, getting people's attention towards the music & good advertisement for the band/artist.
the cons are distraction.. the music video could be a distraction from a horribly put together song, but everyone watches it because it's so entertaining. Music videos take a lot of work and money for a 3-5 minute video on YouTube, it's almost not worth the effort anymore (because TV stations like MTV aren't buying the rights to the video anymore, and instead playing their own reality shows). However, almost every artist still makes them to get their fans excited or to rack up promotion for their new single on iTunes or their new album.
