Performing any of the seventh quality chords, their extensions, and eventually developing the altered chords, is an absolutely excellent way for every guitar player to branch out further with chord practice. Add to that, these extended chord types can be expanded upon - with developing your guitar technique and with their application into your composing by allowing you further ideas reaching into many other musical styles.
Pop-tunes, Soul-music, R&B, Country and even some Classic Rock songs can all have these chords showing up in their various sections. One other cool thing is swapping-out extensions for any of the standard 7th chords. By extending a chord into a; 9th, 11th or a 13th we retain the function of the chord in the progression, (since the overall quality is still functioning as it was when the chord existed as a 7th type). The harmony of the chord progression actually stays the same when extensions are added, all that ends up changing is the chords color, (tonal effect), of how the chord sounds.
Applying extensions is a great way to begin adding more flavor into your; jazz, soul or R&B (or any other style) rhythm guitar - without having to learn a ton of new information regarding harmony & theory.