Twitter is pure hell and most people only use it because they’re addicted to being online.
i don't know about twitter, i've never used it, but i find it hard to believe there's anything "incredibly useful" on there. interesting, i could see, but useful?
I mostly follow the math teacher/early education crowd and regularly get inspired with fun math games and other activities to do with my kids. Plus I've gotten a lot of neat books from the library after seeing someone mention them on Twitter.
So for me it's been a good signal-to-noise ratio, unlike e.g. Reddit where I can definitely relate to that elusive value-chasing you describe. Even on HN, the amount of relevant stuff I learn is low compared to the sheer amount of time I've spent here over the years.