When it comes to the online friendship thing, my guess for knowing someone's height, male 或者 female friends, would just be to get an idea of if I knew them in person, how I would visualise them 下一个 to me 或者 in my life. It's just for the imagination to make online 老友记 feel closer lel.
But if girls are asking from the position of an interest in dating, then girls tend to like guys a similar height 或者 taller than them because girls can feel self conscious if they're taller than the guy, that's just in general though.
Social constructs. In society's eyes the guy is supposed to be taller than them,stronger than them,etc some girls are extremely traditional from a dating perspective but if it's just being friendships. It's about visualizing how someone looks. To get a gauge about appearance.
Well when it comes to friendship I couldn't care less about a person's(male 或者 female)height however if we talk about 爱情 interests than I have a preference for tall guys because I find them 更多 attractive.