The purpose of a reality check is to test whether or not you're in a dream. If something impossible works, you can deduce that it's a dream. If it doesn't, you can deduce that your RC has failed, and try a few more before deciding you might be awake.

RCs are not for the development of prospective memory. Awareness and memory exercises serve that function. Prospective memory is used (in lucid dreaming & RCing) to remind yourself to merely question or to reality check to dreamsigns and other unusual things.

Lots of people don't require a 'physical' reality check- they can review their memory and realize that the timeline of recent events makes no sense, that the location isn't real, that the people aren't real or shouldn't be alive, etc.

If you don't need to RC, if it just happens very often that you know you are dreaming, then congrats- you're a natural.