After a beginner at the organ arrives at a certain level using one of the easy play methods, there typically arises an appetite for more than what a lead sheet and simple chord symbols can provide.
Students, at this point, seek to move to the next level, where they need to be exposed to reading the bass clef, chord inversions, using their feet to do something besides hold down the root of each chord, and begin taking their first steps in a general study of harmony [See blog, Orem's Harmony].
Song albums of popular show tunes, like those arranged and edited for Lowrey organ (photo) by Mark Laub, for example, written on 3 staves giving the left hand and left foot something more varied, but not too difficult, to do, can be invaluable at this critical time.
This is the point where the beginner leaves the beginning behind them, where the right kind of boost from a good teacher will lift the student to the next rung on the ladder and encourage them to climb even further in their learning of organ playing.
A simple little book like this does more than provide the correct notes for the melodic idea, or theme, of a song and its basic chordal framework, as something to play, as it is; far more importantly, it stimulates the musical imagination and gets it working to take the editor's arrangement and spruce it up, add embellishments, elaborate on the printed page, and create ever more interesting and complicated song arrangements, which are the student's first steps in improvisation [See blog, Improvisation, Parts I-IV].
Herein lies its greater value.