Why do some NB people specify their agab in their bios and such?

Hi, I'm a binary trans man and don't refer to myself as afab at all so I'm just curious.

I see plenty of nb people specify their agab on apps like Twitter and Taimi. I thought maybe on dating apps it's to weed out people with specific genital preferences, but I'm sure some nonbinary people get bottom surgery(?) What's the importance of specifying what you looked like at birth?