It can be both, depending on the why. Leaving Twitter has been great for me, but I didn’t leave it because someone was threatening me. I do know someone who left Twitter for that reason.
Politicians, journalists, academics, every celebrity ever, etc aren’t on 4chan (or at least trying to have serious conversations there). This isn’t a good comparison.
Twitter is the public square more than it a news source. The effects of loud voices there lead to global, real world change. Journalists talk to and police each other there. Celebrities influence millions of people there, enough to where people pay them to tweet certain things advantageous to them (“buy these cool Nike shoes!”).
4chan is an anonymous, interest-based forum that is more or less irrelevant to most non-internet people.
> There's definitely some influence there, but the twitter's importance and impact on the world is severely overhyped.
I'm not sure I would make the same claim. Twitter is wildly popular among journalists, pundits, and other members of the media. Due to its outsized importance within these groups of people, I can easily see Twitter playing a large role in shaping media narratives.