Light sparring freestyle gives you a chance to try out new moves and be daring. It lets you take chances.
In hard sparring, as in competition or combat, you can't take chances as you can't risk getting hit. You only use your best techniques, your tried and tested methods and ABCs.
So although hard sparring has it's place, it's the light sparring that will be your main development area.
Hard sparring is for pressure testing.
You can spar light in the points karate and freestyle SC, and also boxing, kb and Thai.