I don't think that "competition" with rules and such is the answer, but for imediate use in self-defense, you need to be able to try out whatever you are learning against someone who is resisting and unpredictable.
The last time i looked m/t does not teach defenses against back attacks, karate doesn't cover ground fighting, boxing does not show control holds against non violent attacks, all systems cover some parts of self-defense, but they all fall short in the long run. self-defense is its own (art) style. karate sparring teaches control of distance, timing, how to close the distance, and that is when fighting starts, whether hitting, kicking, choking, using knees, continuously driving through your opponent until they are no longer a threat. to be effective you must first have a clear vision of your goal, whether street fighting, competition fighting, controlling an opponent, as in law enforcement, or survival/self-defense.
You need a resistant partner to be able to practically apply your training regardless of style or system. How you work up to that is strictly up to your instructor and system.
Aging, health issues and Martial Arts. - Martial Journal
