Universities used to be the pioneers of online communication but they seem to have become a lot more conservative in recent years.
Mastodon can already be a drop-in replacement for Twitter for many use cases. The biggest hurdle are, as ever, network effects. Not infrastructure, not features.
For me personally most of the people I care about already are on Mastodon. It was a smooth transition for me personally and I don’t miss a thing. All that needs to happen is for that to be also true for you and Mastodon is a drop in replacement.
The biggest issue I can see developing is a Gmail-ification of Mastodon (with a lot of people being on a single instance).
That would be a pity – but in terms of freedom e-mail is still pretty great.
The fact that it's still useful makes it more important to switch, not less. You're putting career before your basic values (I'm guessing) and as an academic I would hope you know that's wrong and have the honor to correct it.
So, all told -- I don't think there's a lot of productive work (i.e., research) directly going on on twitter, but that doesn't mean that it isn't still making important contributions to the profession.
Also, yes, the water cooler is fun