IMO, knowing and playing other styles of music will help you improve your skills. Different styles may use different techniques, and learning all these different techniques will let you input variety into your playing.
Mudvayne's drummer Matt McDonough is a heavy metal drummer, but some of his playing has influences from jazz.
Tre Cool, drummer of Green Day, played the triplet swing rhythm on the song Holiday.
It's not right to say that other genres suck just because you don't like it. Because if you do, you'll never improve.