For those that can afford it racing is a great sport and has so many levels and as racers grow they obtain various license depending on their training and shown expertise.
I worked in track safety for a private race track in S. Georgia and we hosted club racers of all types except dragsters. No visitors were allowed, it was a private race track.
It would be unsafe to have full outright racing with beginners and experts mixing it up on the track. Equipment, carts, cars and insurance are too expensive to risk experts and beginners who may or may not know to read race flags like yellow, red or black flags and what a move over your going to be passed flag looks like.
So groups are separated into beginners, novices and experts with each striving for a higher class. Racing classes given by the racing group to each class helps advance drivers. It's more like an apprenticeship for racers. One caveat is if you keep advancing, it takes tons of money to play with high performance cars.
Just an overview kinda