All well and good, seasoned travellers - but I suspect that idiot broadcaster's audience were not regular passengers.
It's a matter of optimisation: the more readiness/knowledge on the part of any given passenger, the smoother an evacuation will be.
Factors include the intrinsic stress of take-offs for most passengers: e.g. reading the safety card of itself has a de-stressing benefit. (sense of doing something active in a powerless situation)
And don't make the mistake of thinking that as a seasoned passenger you are necessarily going to perform better in an emergency. Passengers may believe they have taken in all the information many times - but, again, the stress component lessens their ability to take it in, and recent repetition becomes important. In a state of confusion and mayhem you will remember recent repetitions, and recently rehearsed scenarios.
I expect there is a relevant de-stressing component in the safety message for the flight crew as well - they don't know who among their passengers is a seasoned traveller ignoring the briefing because they are actually familiar with their location and the layout of that exact plane from the very last time they flew (in an emergency situation, any analysis will be an impossibilty other than in the coolest of customers). So if everyone is watching, learning or re-memorising, so much the less concern for the flight attendant that one or two might hold things up.
In days when I knew less about aircrash survival I'm guilty of ignoring the safety briefings and even failing to check the exit plan thoroughly. Not these days. These days, for example, I actually count AND discreetly pat the back of the seats to the exit the first time I head for the toilet, because that reinforces the message for a day when my brain will be relying on recent rehearsals. I don't go so far as to crawl on the floor, but I also rehearse a floor crawl past those same seats in my head.
Rehearsed information is of more use. This I knew from professional knowlege in other areas, but interestingly it was reinforced in a doco on air safety aired recently in Australia.