Because they might be physically impaired in some way. Or have severe Repetitive Strain Injury (RSI).

In addition to the other points above, i have found that in some workflows I have found that using talon and cursorless i am faster than I was using just a keyboard and mouse. I have had some bad RSI flare ups over the past few years and they have been a lifesaver getting me though my undergrad and most of my masters. Even during the times in-between flare ups i found that using them to editing a latex document was much more convenient being able to reference paragraphs/sentences/words and then change them or move them around.

TBF, you need working hands to use hands-on computers.

Plus, the offline part could make a good starting point for a DIY personal assistant.

That said, their "getting started" sounds...esoteric.

>There normally isn't any output but you should be able to type "hey" by saying "hoof eve yank" and transcribe a sentence after saying "scribe". You can terminate it by pressing Ctrl+c or saying "troll cap".