Strokes evolve over time and occasionally, usually once USA Swimming has adopted a change, MCSL has to revise its stroke rules.
I didn't usually swim breaststroke back in the Old Days. From my limited observations, swimmers were either natural breaststrokers--if a swimmer naturally stands with feet turned slightly out, forming a sort of "V" with his/her feet, that swimmer might just be a breaststroker--or they weren't. The natural breaststrokers swam breaststroke and maybe IM; the non-breaststrokers swam everything else.
Anyway, on the rare occasion that I got stuck swimming breaststroke, I would try the trick some breaststroker on our team must have taught me--I'd go to the ladies' room, grab a bunch of paper towels, and stuff them in my swim cap before I reported to the clerk of course.
Why in the world would I do such a bizarre thing? Because the rule for breaststroke used to be that the head could never be submerged. The higher--the "larger"--the head, the less chance water would rush over it. It wasn't until 1988 that the breaststroke rule was changed to specify that the head must break the surface during each stroke cycle instead of being above the water throughout.