The keyboard system differs from the more traditional piano education. Usually playing songs on a keyboard involves learning how to read music in the treble clef (for the right hand) and playing chords (in the left hand).
Why they work:
This system suits students of all ages, who would like to learn songs for fun and in general focus on popular music, as there are usually no exams involved. Students still get to learn the fundamentals (including theory), but because the focus is on popular music, they also learn some other important skills such as how to play by ear, how to make up little pieces or even improvise etc…
This is possible because they learn chords from the very start (these are the building blocks of popular music), and since It's possible to play hundreds of songs with very few chords only, as progress is made, students start to recognise chord sequences that eventually allows them to pick up songs by ear among other benefits.
Keyboard lessons are more suited to students who:
Would like to focus on pieces they like (popular music)
Would like to learn chords
Would like to make up their own little songs or improvisation
Learn how to play by ear
Also would like to explore different features found on keyboards such as playing with different sounds, accompaniments etc...