The gravity car concept solves my biggest complaint about today's slot cars - they are just too unrealistically fast and "glued to the track." Decades ago, when slot cars were invented, they traveled at a more-or-less realistic speed, whereas today's slot cars are traveling at a scale 1,000 mph or so. With the car now held on the track by magnets, the driver hardly ever has to take his thumb off the controller switch. This gravity car idea yields much more realistic action (even though the camera speed has to be cut in half to get there).
I bought a Drag Track, drag set, from Summit Racing in 2014. It is a blast. I enjoyed it so much I went to purchase another one last year and they don't make them anymore. Found a complete set on Ebay last year and purchased it. Now I have 2 and can make launching ramp and the straight away longer. I must say it's passes time fast on a cold winter afternoon.
These showed up on my YouTube feed a year ago and I've been a fan ever since. Great fun and the really funny thing (after reading the article) is that I watch them at 2x's speed which kinda negates the halving of the action he does.