why is it limited to metal when most other rock bands use the same instruments in their music?
the difficulty of playing an instrument is irrelevant, it's how difficult the piece you're playing is. and even then it doesn't really matter because having a difficult piece to play but at the same it being a song that's not very enjoyable is dull (ex. some Necrophagist and Rings of Saturn songs)
^fine, rock too.
Vocalwise, any genre can play with it, but metal, classical, and rock have instruments while the typical pop and rap use a computer. Metal, classical, and rock use one of the hardest instruments to ever learn, thats why i chose them