I know a lot of piano players that can't play arrangers. Most of them can't understand the concept of playing a chord with the left hand, then releasing it to do something else (fills, variations, change settings, etc.) all while playing riffs or melodies with the right hand, while singing, using both feet to control such things as vocal harmony, sustain, volume, etc. All this while thinking ahead to what song to do next that would be most suitable for the crowd and mood.
But they will smile knowingly and say "that thing plays itself, doesn't it".
And how many times have we heard women say "let it play by itself and dance with me". Well maybe not too many lately.
DonM