yeah, this is an important aspect of expressive controllers generally…
you will be surprised how good relatively simple sounds can be when you get more direct control.
(conversely, you can muddy things up if your not careful )
many factors to this, but I believe its down to a few (related) aspects
continuous control, high resolution, poly independence
the sound is continually changing because your holding the touch, and moving ever so slightly , which is being picked up due to high resolution… so the sound is always evolving , then when you add multiple touches they are also slightly different.
with traditional keyboards we try to ‘fake’ this movement, with envelopes, lfos and random elements - we try to inject back the ‘life’ , that we lost due to not capturing out ‘input’ with sufficient ‘finesse’
that’s not dismissing keyboards, percussive, non-continuous sounds are very cool too… my favourite instrument is a piano… which needs none of this,
but its great to have options… (esp. in some ‘genres’ of music)