I think you’re just being contrarian for no reason. The market for specialty input devices is much smaller compared to “normal” keyboards but it still exists and has become much more diverse over the past decade, with many new niche products being launched. This isn’t even the first commercially available chorded keyboard. From the video, this particular iteration seems to be marketed towards mute people and I’m sure that they or people with other kinds of disabilities are probably glad to have any products at all available to aid them in daily tasks. Not every product or company needs to participate in a high volume market. Apparently, the chorded inputs can also be reprogrammed and it can work in a normal keyboard mode, which should make it more flexible than something designed purely for stenography.
A steno machine is just a kind of chorded keyboard.