It seems that many people don't understand that the music business is very big and important for apple, and buying Beats is a way for them to get a music streaming service that they can make into the biggest in the world with their 800 million iTunes accounts and all huge music deals they already have.
And Beats is already very profitable so the huge amount of money Apple payed for it will be very fast earned back. So this is pretty big and an important deal for Apple and the end user. Spotify, Rdio and more will get a very big competitor in Apple now when it comes to music streaming.
And Apple have to do this because people doesn't buy as much music anymore, more and more are using music streaming services instead, so they are loosing ground with iTunes.