I mean - this seems like you don't actually use the service. I do JS development, and I can pretty reliably get someone like Dan Abramov or other JS 'rockstars' to look at/comment on an issue if it's required. Additionally, I can see these people interact with their peers and discuss ideas. Fundamentally, twitter has become a platform for idea exchange and conversation that has professionals on it, discussing things professionally! It doesn't really get more meaningful than that.
So for your JS example, why would you attempt to reach them on Twitter when something like Github would be so much better? Create an issue on Github, point to the exact line of code that is a problem and wait for a response?
How do you ask a meaningful question about source code / software development in 140 characters? How do you get a meaningful response in 140 characters?
Because it's not just about issues - I don't exclusively want someone to interact with me in a setting that's centered around the content. I would preferably like the experience to be more free form and open to a wider audience. Incidentally, I don't think the 140 character limit has ever really bothered me. Most of the time I text shorter strings than that - if I want to have a longer conversation I'll either send multiple tweets, or move to DM/chat.
