If you weren't allowed to do this they would have prevented it. This is not a glitch and not and exploit. You are simply performing a ProTip that they give you to jump higher with assault. I guarantee you will never get kills from up there, ever. There was three people doing this a few matches ago and they can do no damage to someone that is playing.
Yeah, imo it's a pretty useless spot. I've never seen anyone get a kill up there. If they get anything they'll get assists.