1) Pilot thinks there may be damage/malfunction and does a low pass so that the Tower/Ground Ops staff can have a look. This was evident in a recent one I saw where the pilot had a nose gear fault. It took two passes, but they were able to confirm that the nose gear was NOT down and were still able to have a successful landing.
2) Student pilot either has mechanical issue or in-plane pilot becomes incapacitated. Tower/remote instructor tells student to do multiple low, slow passes at increasingly lower altitudes and speeds to get used to taking the proper heading and control inputs until the final pass is so low/slow that the landing essentially happens naturally.
I'd be flabbergasted if the FAA bans this type of thing, in both of these cases I personally saw (and I'm sure many others), this procedure saved lives. Why would they ban this?
For non-emergencies, I love watching and hearing a good low pass, but these impromptu displays could get annoying for airport neighbors and they have killed people when someone gets a little too sporty in their display. If the airport Saturday morning breakfast low passes all went away, I'd be slightly sad but it's probably for the best.
Trent's case is an interesting one. I don't know what his actual intent was, but unless it was clearly a show-off-only low pass, I think the FAA should let it go.
If low-passes are a significant safety risk, then the FAA should prove as such and write a clear rule specific to it, IE a maximum speed over the runway. All kinds of air safety seminars + CFIs are trying to teach go-around as a normal maneuver that should be practiced regularly and then the FAA basically says a go-around could cost you your license.
I’m a lot more sympathetic to noise complaints against 2700 RPM (prop tips nearly the speed of sound), high-power, low passes that have no operational need.