Keijo's not in a much different category to Strike Witches or something like that, I'd think. Strike Witches also worked because they took the core concept seriously. Anime can be good at that: taking an absolutely batshit crazy idea then running with it as if it's a serious idea. That's kind of what sets this sort of thing apart from how American or British would do it. In the west if you have a crazy idea, then they want to make it "Zany" on top of that. But it works far better if you just roll with it.
I'm surprised you never heard of No Game No Life btw, it was a pretty big deal when it came out, got a lot of discussion here. It has reasons to love it and reasons to hate it, which makes it something worth talking about.
But you might just not be up on the whole titty-powers genre. There is in fact a genre. Keijo is a middling fun series, but it's just not anything revolutionary and certainly isn't overthrowing any tropes. It's parodying sports animes, not fanservice animes. It has special "titty power moves" because every character in high-powered sports series comes with signature moves. e.g. Kuroko's basketball and all of the named basketball-playing powers that different characters have.
That's what Keijo is parodying, "powers" based sports series, but with hot girls and the powers are lewd. It's part of a trend "parody <thing X> but with hot girls". e.g. Walkure Romanze which is "hot girls and jousting" or Saki, which is "hot girls and mahjong". Recently we had Bakuon, about "hot girls and motorbikes". And the guy who directed Keijo also worked on Upotte - it's about sexy machine gun girls (the girls are anthropomorphic machine guns), which itself was influenced by the whole mecha-musume anthropomorphism thing of Strike Witches, Kancolle etc. Then of course there's Daimidaler from a couple of years ago. it's about a guy who powers up a mega-robot's core by fondling boobs. That's his power. think Shinji from NGE but he has a molester power.
And the cake is still taken by Seikon no Qwaser ... the story about magical battlers who get the powerups from virgin's breast milk (direct from the tap, so to speak. YMMV). Is that "playing it straight", "subverting it" or "running with it at full speed". The answer: all of the above. it's (1) actual fanservice, (2) subverting the idea - the boobies are a major plot point (3) far more over the top than Keijo ever dreamt of becoming.
There are an endless stream of such shows parodying every possible other genre and activity.