For reasons I won't get into, 24fps is the de facto standard for movies. It's sort of the bare minimum for smooth motion, and anything wanting to look "cinematic" tends to be filmed that way. In fact most content is filmed at 24fps, meaning that content filmed at 30/60fps is quite rare. Sports will be at 60fps for maximum motion smoothness, meanwhile dramas will sometimes film at 30fps, leading to the soap opera effect. In the case of Tokusatsu GAGAGA, it's filmed at 30fps like a soap opera.
There's nothing particularly novel about filming the toku sections at 24fps, but it's one of those details that showed someone cared about authenticity. A lesser production would use 30fps throughout (and there's an argument to be had that mixing framerates isn't a good idea to start with, since it leads to juddering on the 24fps sections as frames get duplicated).
I showed it to a friend who is an anime fan, and sometimes J-drama fan, but doesn't much like tokusatsu. He thinks it's too childish. I showed this to him and he didn't really get it like a tokusatsu fan would. He understood the gist of course, but some of the finer details went over his head. I think it's better to just pick a favorite episode of a tokusatsu show if you want to introduce it to someone, and explain to them what you like about it. If they like it, they like it, and if not...it happens. Of course my friend doesn't make fun of me liking it or anything. I mean, he likes anime and video games and comics and stuff so he has his own fandoms. Finding tokusatsu friends in real life is pretty difficult, actually. 
