Chess might not be a great example, given that most people interested in analyzing chess moves probably know that chess engines exist. But it's easy to find examples where this approach would be very helpful.
If I'm an undergrad doing a math assignment and want to check an answer, I may have no idea that symbolic algebra tools exist or how to use them. But if an all-purpose LLM gets a screenshot of a math equation and knows that its best option is to pass it along to one of those tools, that's valuable to me even if it isn't valuable to a mathematician who would have just cut out of the LLM middle-man and gone straight to the solver.
There are probably a billion examples like this. I'd imagine lots of people are clueless that software exists which can help them with some problem they have, so an LLM would be helpful for discovery even if it's just acting as a pass-through.