Requirements vary. It certainly can't produce really complex visual designs, or code a designer would be very happy with, but I have a hobby project work in progress where gpt4 has produced
all of the CSS and templates. I have no doubt that the only reason that worked well is that it's a simple design of a type there is about a billion of in its training set and that it'd fall apart quickly if I started deviating much from that. But if t produced both clean CSS and something
nicer looking than I suspect I would have myself.
A designer would probably still beat it - this doesn't compete with someone well paid to work on heavily custom designs. But at this point it does compete with places like Fiverr for me for things I can't or don't want to do myself. It'll take several iterations for it to eat it's way up the value chain, but it probably will.
But also, I suspect a lot of the lower end of the value chain, or at least part of them, will pull themselves up and start to compete with the lower end of the middle by figuring out how to use LLMs to take on bigger, more complex projects.