How can knowledge of the musical form AABA help you learn a piece of music? Once you learn the first A section, you will already know enough to play three sections of the song.
Using labels like A and B to identify phrases also tells you which note to play.
All songs in AABA form use the same notes and chords for their melody and accompaniment.
AABA songs are easier to play, and therefore easier to learn, than other songs.