Alt-text is really a big cultural differentiator for Mastodon. Twitter has it, but it's pretty rare to see people use it. Threads doesn't have it at all! And with regards to scicomm specifically, it's a perfect example of how accessibility improves the experience for everyone. I can break down a dense, hard to understand figure that people with vision would still find confusing. To me, alt-text is a non-negotiable requirement of good science communication.
@dantheclamman Mastadon was my first experience of Atl-text. Seeing and using it has changed how I think about how I describe the world to myself.