Why are Beats by Dre so popular?

So everyone knows they headphones: Beats by Dre. Sure, they are pretty good headphones in my opinion. I've listened through better headphones. However, hundreds of people at my school have them, and my best friend has been freaking out because she just bought herself a pair (more like used her parents' money). In my opinion, they are WAY overpriced. I have a pair of Sony headphones that were on sale for like 20 bucks that are almost just as good, except for the noise isolation and volume. So I would like to know why everyone has to have Beats by Dre, despite the fact that there are better and cheaper headphones out there.

Oh, and also this. Why do kids who know nothing about music and don't listen to it very often who get Beats have to get Beats Pro? Aren't Beats Pro meant for producers and engineers who actually need the extra extreme quality?