I've never seen the appeal of cursor either, but then I'm a decades-long vim (now neovim) guy and don't use IDEs in general. But for me claude/codex TUIs are a great way to fit agents into my workflow.

My suspicion is that it's a way to break into more developer workflows for Grok, even if the market share is relatively small. I've never used grok and don't plan to at this point, but I have highly respected friends who say it is pretty damn good, and some of them even started using Cursor because of this pairing, so anecdatally at least it does seem to be working.