It's true that being a bit small in height but with a big frame is generally an advantage over a skinnier lankier fighter. Problem is when you have extreme weight cutters who are not only taller than you but also the same or bigger frame.
Being tall doesn't really have much advantage on its own. Small ones sure but nothing major. it also doesn't make that much of a difference with girls. If there's a good looking guy in shape who's 5'8 he'll be more appealing than an average 6'4 guy. Against a good looking 6'4 guy he's probably at a disadvantage but how many in shape guys with good faces do you see around? I'm tall so I know what I'm talking about.