I've used that type of plug in car, tractor, and riding mower tires. I was one of those who insisted on breaking a tire down and putting a patch on the inside for many years. But most tire places I know of will still patch the inside on request, but if not requested, they use the plug and guarantee it the same as if they'd put a patch on the inside. In fact some claim the plug is even better than the inside patch, especially with steel belted tires. The theory being that moisture and dirt can still enter the hole from the outside if it was patched on the inside, while the plug effectively plugs or fills the hole so nothing can get in from the outside in addition to keeping the air from getting out.
I was fixing flats when the first new cars came out with tubeless tires and I used some of the earliest plugs, including some that were not very good. That's the reason I stayed away from plugs for many years, but I believe the modern type of "plugs" are very good.