So, the thing is.. color codes are nothing more than cosmetic changes and cannot effect gameplay by all means.
This thought is kind of a hit or miss either way you look at it, but it would actually be kind of cool imo if we had the ability to use our favorite colors on Mario, and all have our own enjoyable colors to look at while speedrunning. I also think it would give us more diversity in some way; ways people could possibly recognize runners in the community by the colors they use i.e. how the competitive Smash scene use different colors throughout the vast selection of colors to choose from.
Yoshielectron has conveniently provided a perfect color generator that allows us to customize Mario's colors to our liking. I think something like this would be super cool in the SM64 speedrunning community tbh.