Hahahaha, of course properly using a condom can also reduce your risk of contracting an STI, and the risk of pregnancy.
At any rate, yes. I concur with everyone else's evaluations of the differences between one night stands, casual hook ups, and relationships. But for the record, relationships are scary and a lot more difficult to start up. Casual hookups have all the fun of sex without the minefield of a relationship. It sounds cheap or sleazy, but bear it mind it also depends what you want, and what the other person wants. If neither of you really wants a serious relationship that doesn't mean you can't still have sex.
Also I dunno, it's also possible to have a retroactive one night stand. You meant to hook up with this person again, but for whatever reason it never ends up happening, and voila, retroactive one night stand! Though that's not really the same thing. And again, as long as both of you know what it is, there's nothing wrong with a one night stand either.