The truth is that some Pokegirls look better and should be drawn with cowtits(May, Rosa), and others should be drawn flat. Hilda's charm point has always been her ass, and her legs, which has been highlighted in official art. Esentially, May and Rosa have "big tit energy", so the fandom versions of them /feel/ accurate even if they're not. Hilda's energy is different, and fanart often does not capture her "feel".