The car tire guys are probably a lot more honest in a way. At least they're conceding that they don't use the capability of their tires. I love when my friends call me for advice on tires and ask questions about grip and warm up time. Meanwhile they've never used the outside inch and a half of their tire. I think they just regurgitate terminology they heard watching MotoGP.
This has been done for a long time. If I recall correct a number of people on FJR / ST bikes do that. Not something you should try on a Versys or a KLR
"A car tire is not practical for a sport bike even though its cornering traction is probably as good as a motorcycle sportbike tire and can maintain similar speeds thru corners where the car tire becomes impractical is rotating mass, you cannot accelerate out of corners as fast with a heavier tire. The bike with the car tire will never keep up with the one with a bike tire" Stolen from the site
I recall a long time ago seeing somebody using one of those space saver spare tires on his motorcycle. It looked a bit scary.
This. When I had the wing, I went through a set of tires about every 6-8000 miles. The fronts would cup/scallop, and the rear just wore. Also, the underside of the floorboards was always scraped and scratched.