Thoughtful writing ! Completely agree with you on the toxic part of twitter, which, if I may paraphrase from your April 7th writing, promotes quotability, even if it distorts the context it was said. Not to mention that it's the hotbed of attention-seeking trolls.
However, I think one aspect of it is really good. It is that scientists, who most people don't have a chance to know in person, sharing their work, and importantly, their life, both ups and downs, like sharing pictures of them sleepy and in pajamas on a much earned Sunday. I think these aspects help normalize scientists, let society to know that they're normal human being, not all are mad and not all wear white coats. Furthermore, I think it'll connect with more kids and inspire more young generations.
I once had similar thought of quitting twitter. Then found out Medium, which seems a nice platform to express a thought or opinion without being limited by word count or the fear of being attacked with some random lazy words. Besides, I had much better control now, after reading someones suggestion or only tweet/engage with tweets that is either useful or funny. I add one more, that to engage with very personal tweets, like someone getting a job or being promoted or personal loss.