I've been using a Shake Weight for decades -- only I call it a cocktail shaker. Hasn't don't much for my muscles, but then maybe that's because I drink the contents afterwards.
Actually I thought the same thing as Ellen and her audience did when I first saw that TV commercial being run. I was like -- are they serious with that demonstration? People will be falling out of their chairs laughing, just like they did on Ellen
The only advantage I can see is for some husbands, whose wives will become more proficient with a skill they may presently lack. Hmmmm... I wonder if my partner would use a Shake Weight if I bought him one?