It's kinda applied in the 100% category.

Only reason I personally think a mod would do it is if they also added a separate "All Red Coins" category.

Personally, it seems like a cool idea, but it's most likely gonna be an empty category (as in nobody would care to run it.) I'm also pretty sure this has been thought of in the past as well.

If it were a thing though, it would change up the egg count / lessen the intensity of the game.