Now I see these semi hollowbody guitars, and I wonder could you use one for normal rock music or are they mostly just blues and jazz guitars?.
nah, theyre used for rock all the time.

just off the top of my head i saw Josh Homme of Queens of the Stone Age using one on letterman not too long ago.
they just give warmer tone, they can be used for anything really. Even metal IMO. In some ways they are actually superior to solid bodies (with the exception of durability, portability, size).
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"Swing your hips, not your fists"- Cedric Bixler Zavala
hell, i've seen one of the guys from the black dahlia murder (metalcore band) playing a semi-hollow
Fender Deluxe Jazz Bass
Gallien-Kreuger Backline 600
Avatar NEO 4x10
Line 6 Spider III 75
yes you can, the problem is that is easier to get more feeback from these kind of guitars, but they can give you some excellent tones
Paul Gilbert uses one and gets a great metal sound.
So good to see you once again.
I thought that you were hiding.
And you thought that I had run away.
Chasing the tail of dogma.
I opened my eye and there we were .