Aside from killing people in wars what are semi-automatic and fully automatic weapons used for? Skeet shooting/target practice/hunting deer?

Collecting is another use, like some old ladies collect Hummel figurines. A gentleman that lives in my area has a couple of working 50-caliber WWI vintage machine guns in his collection. I don't believe that he fires them anymore though. At $2/round that works out to about $1,200/minute direct operating cost. And they are a heck of a lot of fun to shoot, if you have the money to "feed" them (as you can see from the previous example). There's a gun store about 40-miles from where I live where you can rent one for the afternoon but be sure to bring lots of cash. Ammo ain't cheap. There may be other esoteric civilian uses for them that I'm unaware too.

Fully automatic firearms aren't real good for killing anything though. A BIG part of killing something with a firearm is actually striking the target in the K5 zone and after the first round is fired they're no longer "on" the target. So if only that first round really counts then why not use a weapon that has supreme accuracy with that first round, like a bolt-action or semi-automatic. 

And speaking of semi-automatic firearms, they're used in virtually every shooting endeavor. You will find semi-automatic shotguns used for all manner of game hunting and on the trap and skeet ranges. Same for semi-automatic rifles and pistols, except change that skeet and trap shooting to target shooting. They're no different than weapons with any other type of "action" in that regard. 

By the way, below is a photo showing several "sporting" rifles. Two are bolt action, one is a lever-operated bolt action and one is a semi-automatic. Can you tell which is which? [Hint, the semi-automatic rifle (Winchester model 100) and the lever-operated bolt action rifle (Winchester model 88) are almost identical cousins with removable magazines that are limited to 5-rounds.]