If the pentatonic scale pattern is built inside the
major scale pattern, what's the point of learning the
pentatonic? If you learn the major scale, you
automatically learn also the pentatonic, right?
This is a great question about learning guitar scales. I could add to it, "If all scales are derived from the chromatic scale, what's the point of learning anything else? If you learn every chromatic note on the guitar fretboard, you're touching on any and all types of scales."
Of course, is doesn't work this way. Guitar scales make unique patterns on the fretboard. If you want to create pentatonic sounds, you must know which major scale notes to skip over, hence pentatonic scale patterns.
Since the pentatonic scale notes alone are so widely used for melodies, riffs, solos and bass lines, it's critical for guitar players to map out and learn just these notes on the neck. It's also critical for players to learn how to execute techniques such as hammer-ons, pull-offs, slides and bends with the special two-notes-per-string pentatonic patterns.