I've got valuable advice from SO over the years. There's overlap with LLMs, sure, but it's frequent to have questions that have no answers published anywhere on the web; SO brings people who know out of the woodwork, who create an explanation that didn't exist before. A couple days ago, someone in retrocomputing got to bank-switch a 1983 Radio Shack box... that kind of stuff wasn't published anywhere, until a guy who used to write games for that box answered that question on SO.