Typical steno keyboards can definitely type single characters. Of course the most sensible use of them involves chords (defined according to a text-specific 'theory'), but you might still use them for mostly single-character entry if, e.g. you were concerned about RSI.
I'm not the one you responded to, but I just wanted to add that it's still not steno. CharaChorder just has chording, but no theories, or whatever you call them for steno. You basically have to memorize every single chord on the CharaChorder afaik.