This is mostly just using the keyboard to manipulate the rhythm/time performance of a pre-configured score. Interesting, but not what most would think of as jazz improvisation.
Not exactly. It is far more random than that. As far as I can tell, it plays random notes from a pre-loaded scale - occasionally chords, and punctuation marks play chords. Backspace plays a descending scale.
The aesthetics of it, including typography and sounds are very nice.
And typing () leads to a special easter egg :)