We currently live nowhere near a TJ's, as central/southern VA lacks in that respect, but we used to live in northern VA, where there are several, and indeed it rocks. For Christmas, my in-laws--both my wife's parents and her her aunt&uncle--gave us bags and boxes of TJ's goodies. :D
To be fair, those do serve a purpose--though to people who show dogs, not your average pet owner. If you're training a dog to gait for the show ring, or need to see how the dog is gaiting, you can't easily do that without another pair of eyes at the side--or a dog treadmill.
(Longer, more tests, in English.)
Only five or six total videos matching those search terms, oddly.
Well, I'm sold! :D