If it's not going to do anything
I don't think characters should be LGBT or at least not have it be a big deal
Like, once I read a book where a huge plot point was how one character was gay. I'm cool with that, it's important for the story.
But if it's not even going to lead to anything, it kinda seems like a Chekhov's Gun to me. That doesn't only apply to LGBT characters of course - I don't think anything about gender identity or sexuality should be brought up if it's never important for anything.
And, I mean, I wouldn't want to read an entire book that's just about LGBT - I'm not interested in that. So if an entire book was all about the problems of an LGBT character, it would just turn me away. WoF isn't really... about that sort of thing, and it would seem out of place to me.