The only thing that it is really useful for is getting possible solutions for simple problems that don’t pop up in search results anymore because of all of the slop that it was used to generate for scummy advertising dickheads. Even then, it’s not trustworthy and requires verification, wasting time that would not be needed if the official docs came up consistently on the first page of search results.
This is my experience. It can be useful for simple things that used to be found with a web search before AI slop broke things. For example, I was having trouble getting a simple CGO program for a POC to communicate with the main Go process. This should have been solvable easily with documentation but the CGO docs are pretty bad and sample code was near impossible to find due to AI slop in the search results. GPT was able to provide the needed sample code to unblock me.