Interesting. Indeed, why not just ask “what would you like to be called?” and maybe for administrative(?) purposes ask the full name.

Naming is a tar pit and even Westerners might like to be called John when their name is Winstonshire. Let’s not even bother.

What is the downside? I’m not seeing it. I see people here recommending to implement logic to handle this fully and I’m not seeing why this would be preferable.