I have never heard the word "Leetcode" where I work, or indeed anywhere other than HN, and I've interviewed candidates for every rung of the IC ladder. Never seen it on a resume, either.
Software engineer salaries are increasing following a bimodal distribution, i always thought you had to be a genius level person to work at FB, GOOG, then i see my own coworkers (whom i consider smart but not exceptional) do the leetcode grind and 2x their salary. I'm pretty much in the same boat with you, i worked mainly outside of SF/Seattle for a long time and i'm amazed how much these engineers get paid compared to other cities.
probably, i only have a outsiders view into the software engineers in that city so my view could be heavily skewed by people who only announce their comp if its high.
You wouldn't ever see it on a resume. It isn't a formal skill. It is what we call the ability to pass data structures and algorithms interviews, which gatekeep desirable positions at places like Google.