I have to disagree with this wholeheartedly. The whole point of this is that you don’t choose from lineart-lineart-lineart but different 2 colored shapes which have different proportions compared to each other.
Your brain can remember those shapes better because of the bigger flat surfaces. There are actual surfaces to remember.
Recoloring them to one color gives no advantage - only the disadvantage of lessening contrast against the BG color
