Seeing cheerleaders in Japanese manga is so weird to me, for multiple reasons.
Even though I have seen it multiple times it doesn't seem particularly common either, usually more of a brief appearance specifically during sports festivals days only like this and not as a reccuring presence around the school, even in many sports centric stories (admittedly I don't watch/read a lot of sports anime/manga, but I have some).
Even knowing it's something that Japanese schools have it still somehow feels almost out of place every time it appears.
Maybe because of going to school in the USA where it's an extremely present activity around and being a sport...