As also pointed out on the R&N forum, what it may do is make life harder for cabin crew when enforcing seatbelts-on regulations - cue the smartarse who announces "But they don't make any difference - your boss said so".
I'd have loved O'Leary to be on the landing into GVA I had recently (in the aftermath of a storm) and tell me there's no such thing as turbulence in Europe anymore. When the aircraft fell about 20 ft a couple of times on approach, I was really rather glad of my seatbelt. Shame Mr. O'Leary couldn't have been there to demonstrate the efficacy of standing up and "just holding on to the handle"
