[artimaeis]

Another advantage musicians practiced in reading sheet music have (assuming they're also practiced in the general play of their instrument) is that music falls into various scales and modes. Learning and practicing the scales and modes in different ways and patterns allows musicians to have a wide set of skills that can be quickly applied to most music.

[bluGill]

Note that there are different sets of patterns. Jazz and classical music are different enough that you can be good at one but bad at the other. There are rhythms an chords in each that would never make sense in the other. Of course plenty of musicians are good at both, but it requires more effort.