I think we overuse dunning kruger. “useful” is very contextual. I would agree that for many people it would take some specific and dare I say unusual circumstances where learning another language is particularly useful to them. There’s some use in that you get a bit of a puzzle to overcome, you can potentially eventually get good enough to consume content in this other language (though one thing LLMs are pretty good at is translation), maybe you get a more direct exposure to Dovstoyestky (sp?). Cool and all, but probably not going to get them a better job or help them with most life tasks.