I'm not an expert, but I'd say I'm a strongly average vim user.
But even at that skill level with vim, I haven't seen an area where LLMs would increase my velocity.
Quite the opposite. It would completely interrupt my flow to have to constantly stop and do a code review while I'm writing.
With good plugins, templates and macros in vim/vscode - velocity writing code isn't the issue.
The stuff that takes all the time is UX tweaks and reasoning about architecture, business constraints, and the correct level of optimization for the company's maturity.