1. What I am realizing is that a pianistically oriented arrangement of a popular piece is just as pedagogically useful as anything "classical". The only difference is that students actually like the piece before they begin learning it and love to practice it. Aspects of technique, balance, tone, phrasing, and pedaling are all relevant to teaching "Glad you Came" and "The Pink Panther".
2. Opportunities for collaboration. When a student learns the accompaniment to "Someone like You", the opportunities are endless. Pop trios, drum accompaniments, guitar accompaniments, duets with me or another student are all possibilities. Students are not just playing their favorite piece, they are gaining stronger rhythm skills, collaborative skills, self awareness, and greater knowledge of music in general!
3. Theory skills. Chord tabs in popular music arrangements open up discussions about music theory. I am now easily training even Level 1 students how to hear, write, and play primary triads in all keys. I even had Level 1 students playing I V I chords together in a rhythm ensemble.
I really believe that because of student's interest in a particular pop song, in ways that a Gurlitt or Heller piece cannot interest them, these ideas are possible for elementary students.