I'll add another view of how many keys. What does it lok like in a preformance ? Sitting or standing behind a tiny keyboard can look amateurish to the regular crowd. Recently my friend and his brother who both play keys made mini Grand Piano shells to look more professional.
Why does Elton John still sit behind a 9' fake paino shell ? for us mere mortlals we have to consider the moving hassels so its a tossup.