[unwind]

Uh in case someone doesn't know. Stevie Wonder is blind. Having him test a non-tactile instrument is non-obvious at best.

Obviously he has a couple of metric tons of experience as a musician so can probably make a potato sound interesting, but still ... odd choice.

[Zuider]

Stevie wonder was one of the pioneers of the Fairlight Synthesizer, which was possible for him to use because it used a text interface navigated by arrow keys, rather than a fiddly GUI with unpredictable placement of drop-down menus. Arguably, a touch-screen GUI would have the same predictability (because of consistent placement of active elements) as the Fairlight text screen. In short, rather than being a tasteless joke or a stunt, it was an instrument that he could profitably use, which was demonstrated by the fact that he actually could use it.