Considering how spoiled we are with the tech we have, it seems entirely possible to me that once portals are possible, they’ll eventually be cheap enough to find such mundane uses. Pretty mind-blowing. (And I totally love the sky-diving idea!)
HA! I can lick my elbow with out a portal gun!
Back scratching. That’s the first thing I would do if I had a portal gun. You bet your boots I would.