Printing a label like he did under the buttons is a solid idea.
The vocoder doesn’t have to only be fed via the mic and a voice. Other audio works well too, though he did not demonstrate it.
My impression, on the layout with the audio path along the top, and modulations and extra across the bottom, was it makes logical sense and was easy to see. You could play this synth easily without menu diving, except for the manual latch button as noted.
Very nice synth for your own sound design that seems very clear and immediate. You have a good choice of oscillator engines, which i like. Seems like the price fits and makes sense, assuming the Black Friday sort of sales with $150 - $200 off occasionally.