I think the primary difference here is going to be muscle memory. Both require creativity (to varying degrees, of course) but piano requires physical, hands-on

I think the primary difference here is going to be muscle memory. Both require creativity (to varying degrees, of course) but piano requires physical, hands-on rote work rather than purely intellectual study. There's value in "the study of music" away from the instrument but there is no substitute for hours spent practicing, playing, and performing. He talks about "practice" - practice playing chess is often against a computer or a previously played match's moves. Practice on the piano though involves you playing exercises, pieces, and or just playing around. The other difference is the definition of "good". There is no 90% in piano - you won't "win" at piano. You don't get "points" for playing a recital and there is no "#1 in the world". So I think "good" is relative when it comes to music/art whereas it's a concrete for sport/game. You might think "good" is "Playing along with my favorite recording" while I might rate "good" as "Able to play Chopin's hardest pieces".