so I catch the fish, then what? should I set it free or eat it?

It seems unlogical to spend so long trying to catch a fish then to let it go. however, i dont like to eat fish. is it purely the thrill of the catch that makes fishing so fun? why do all my friends enjoy catching fish then letting them go? seems like their favourite pass time while camping but ive been putting it off on the basis that i dont like fish. Can someone convince me otherwise?

Also does the hook etc hurt the fish/have long term effects on their health.