That is so shady.

I can see why you think that but Asciinema's whole original purpose was to share quick recordings. IIRC you actually had to go out of your way to just save locally, as it's main advertised and very obvious functionality was that it was uploaded. They've since made things a little more flexible, but I don't perceive it as being shady. If you used it you were most likely after that functionality.

It's kind of justifiable in the sense that it's more convenient in the usual case. You say `asciinema rec`, do your thing, and then you have a secure URL to share with somebody, and you can make it public with a couple more clicks.

Actually I think this has changed, because when I tried this just now, it asked me

   (s)ave locally, (u)pload to asciinema.org, (d)iscard
   [s,u,d]? u

It was developed as a tool for the website, not a general purpose screen recording tool.

The latest version has evolved to be more general purpose without assuming the upload.