To avoid the grabbing of baggage, it suggests it could be a good idea to have your passport and wallet in your pocket, rather than in a bag in the overhead.
So you emergency evacuate in a fire, you've no passport, you've no money, no credit cards. Yes the airline will presumably look after you to some extent, but I doubt you'd necessarily get a replacement travel document so easily when you couldn't prove your identity. Similarly, shopping for clothing, unless you were issued a fistful of currency.
One problem in such an evacuation is do you leave your necessary medication behind and rely on the airline/airport to sort you out some more? Then you have the difficulty of convincing the local medicos that you should have these drugs when you've no documentation.
So you can see why some people might really need to grab their bag.