It’s not that I could never play in-tune chords on Continuum - without using its pitch quantizer(s). It’s just that I decided I’d rather have an Osmose and use its more familiar interface to make music, rather than spend the necessary time and effort to play chords on a Continuum.
You OTOH are free to pursue this skill if you like.
My comments are based on trying the Continuum at Discovery World in Milwaukee. Sadly I did not try the pitch quantization while I was there - whether I couldn’t figure it out or I simply never thought of trying, I just cannot remember.
The fretless instruments I have played include viola, electric violin, cello, fretless bass, and fretless guitar. What they have in common is a neck that is conical - you can roughly feel where pitches should be by the thickness of the neck. Also, consider this image
You see where the neck meets the bout? Players learn to use that as yet another physical landmark to assist in pitch location.
On the Continuum, your only pitch reference is visual. There is no physical landmark anywhere for tactile pitch location, unlike the other instruments that I mentioned.
Again though, like I said, if you’re committed to mastering the art of playing chords in tune on a Continuum, good luck with that.