Seriously though... I did a contract for Jef in the early 80s and he showed me the Swyft card. Was happy to buy one of these things when it hit the shelf (though figuring out where to buy it from was kind of difficult.)
The keyboard doesn't have as good a feel as you might expect, so emulation will let you use a decent, modern keyboard. I still have a large box of floppies so that's not an issue. In the 90s I hacked together some FORTH code to read / write documents over the serial port, but it's a bit fragile.
Anyway... It's worth checking out. The only thing I would change would be up and down arrow keys. I think Jef had a philosophical problem with this which is why it never shipped with them. It's usable without them, it just seems a bit weird.
Surprised the article didn't mention the book "The Humane Interface" which was the book Jef wrote with the philosophical underpinnings of Swyft and IA/Canon Cat. Worth a read. Might be up on the Internet Archive.