What’s the use of talking about it?
What’s the use of crying over spilt milk?
What’s the point of arguing with her?
What’s the point of worrying about it?
A: How long have you been studying English?
B: Over ten years now, but my English is not very fluent at all.
A: Why not?
B: I don’t like speaking English because I’m afraid of making mistakes.
A: What’s the use of studying English if you won’t speak it?
B: You’re right. I should try to speak out more and not be so afraid of making mistakes.