Sending nudes is an artform- it can be arabesque, or grotesque. It can be of looks, or "truth". It can be of aesthetics, or enlighten one on what "it" is. Regardless of what it is, it is a form of art- the exposé of the hidden.
a post-modern art brut about ethereal earned-taste topics that makes one think in unprecendented angles, and forces one to leave their comfort zone, trying to see in hyper-eucledian perspectives. The desire to learn really is a sisyphenean mentality; to learn and to still end up foolish in order to learn again, for the secretive to remain secretive, even after getting under the spotlight
This, I think I look hideous and I'm not sure what my gf sees in me! I mean I'm relatively thin and fit, but I just don't understand how anyone could be attracted to the male form. It's just not hot to me, so I don't know how to make it look pretty in pictures.
I think a better question is "what do the nudes you like look like?"
Like, if you're a straight male you're never going to be turned on by your own nudes but I know for the majority of straight men they aren't looking at just closeups of vaginas or boobs. Translate that to the male body.
I don't think that's it; I'm gay and get nudes from other gay guys. Results are still consistent with the OP's example. I think girls consider the whole body aesthetic more, guys are laser focused on "here is a close-up of my dick", "here is my asshole", "so we ready to go, or?"
Honestly I got sick of women asking for nudes whenever I tried to hookup on POF or Tinder. I'm rather good looking but c'mon, why can't we just go out for tea or a walk in the park before you send me yourself in underwear, unsolicited? Or I join Snapchat to talk to you, and when I say "hello there" you send me a video of you stimulating yourself? Why can't I just see you nude in person?