The hook, of course, is that authors use social media for promo, and no matter how often you see the statistics explaining how little it helps (if at all), it's a free outlet that potentially reaches a lot of people.
I have about 7X more followers on Twitter than on FB. My numbers are (relatively speaking) low on both. Twitter isn't going to make or break my career...but I know people who've learned about my stuff on Twitter, and decided to buy it. The short story collection I'm releasing soon (for large values of "soon"
) only exists because some folks on Twitter told me reading stuff on my blog was too hard, but they'd love an ebook.
Twitter has little pockets of actual value...and there's no consistent way to quantify that value for everybody. I'm lucky in that my follower count is low enough (and my block list large enough) that I don't get a lot of hostility or abuse. For some, it's utterly beyond the pale, and shocking that Twitter's management lets it go on.
FWIW, The Kid is not on Twitter at all (although I'll send her links and threads sometimes). She and her friends are on Instagram, Pinterest, TikTok, and curated Discord servers. I don't know if that'll last as they get older, but they seem much more attracted to usage models that let them opt in to people, rather than opt out.
It'll be interesting to see what happens in the next 10 years.