Really detailed details contain a big huge YYH spoiler, but in general: Togashi has this thing where he'll occasionally have awesome female fighters, but they always have to be de-gendered and desexualized somehow. Sexy women, or women who ever fall in love, or women who act motherly, can't fight. So his powerful women always cross-dress, or they're little girls, or they're old women, or they're "deformed." (The two main female characters in Hunter x Hunter each manage to encompass three of the four simultaneously.)

(I made a post about this issue here, but it contains major spoilers both for YYH up to chapter 165 and for HxH up the end of the Greed Island arc.)