@feditips FWIW I do think a lot of sighted users do use the alt text as well. Images are sometimes deleted from caches on instances. In addition there are extentions and tools built into browsers (including Vivaldi) to prevent loading of images for various reasons. Here is my earlier post, which interestingly shows the entire alt text even though the toltip did not.
@feditips I also sometimes use @ihabunek's wonderful Toot TUI masto client from the terminal and appreciate the alt text greatly myself.
Here is my older post as an example
A side note @feditips since you write masto tips. Toot is really nice for automating posting from scripts. My @browserversiontracker and @vivaldiversiontracker are basically just short shell scripts powered by cURL to fetch information and Toot to post it.
With tools like these doing the heavy lifting simple info posting masto bots are pretty straightforward if you have basic command line skils.
You have probably written about these things before but I mention it nonetheless.