Queer is a reclaimed slur! Some people are still uncomfortable with the word even in the West, but many of us have adopted it as an umbrella term that isn't as much of a mouthful as LGBTIA+ (endless new letters to include every identity gets tiring to type out). Queer is a nice catch-all category that doesn't leave anyone out.
It's also helpful if you're part of more than one subcategory– as in, instead of saying "I'm pansexual and transgender", I can just quickly say "I'm queer". (Some people also use "gay" the same way, but "gay" has more specific implications that might feel limiting. Queer as a term is basically limitless.)