Is the reason primarily to due with identifying chords? E.G. major chord = M3 + P5 or V7 features d5 between the 3rd and 7th of the chord. Your program freakin rocks. I am looking forward to completing the 1st course and signing up for the second. Will there be a 3rd?
Understanding intervals is important because it is the foundation of harmony. We build chords from intervals, but its more than just knowing how to recognize the chords, it’s also understanding how specific intervals in chords resolve. For instance, the minor 7th usually resolves downward, however a major 7th should resolve upwards.