As a jazz educator, I try to be careful to not say “use this scale over this chord.” Using scales over chords sounds harmless enough, but we don’t want to be guilty of painting the wrong mental picture. “Using scales over chords” sounds like just running scales, which is boring.
We don’t improvise scales; we improvise melodies! These scales are tools for you to open up new note choices. You don’t want to sit there and mindlessly run scales-that’s not music!
Scales give us structure to our improvisations, but the scales need to be developed into a melody.
Some people like to talk about “pitch collections” rather than “scales” because it creates a different mental picture about what is happening. “Pitch collection” implies that the notes are a palette of notes that will sound consonant (or dissonant) with each chord.
“Scales” brings up a mental picture of running scales up and down your instrument. A technical exercise. While that’s important, it’s hardly musical. Scales are mechanical, while melodies are musical.
Still, chord/scale theory is important to helping musicians know what notes are consonant with each chord. Though some people object to the idea of using scales to make melodies, I have no problem with chord/scale theory as long as the note choices are translated into interesting melodies.