My guess is that they really wanted a take-up spool with a smaller diameter center spool so as to increase the number of turns required by the photographer to advance the film. This would help rank amateurs, assisting them in not advancing the film so rapidly past the numbers in the little red window.
Originally Posted by Steve Smith
Another possibility is that it would allow Kodak to easily separate amateur and professional film at the photo lab so they could direct amateur film to separate work stations with people trained to get the best out of negatives shot by each of these two categories of photographers. Given what people submitted in the days before meters and auto exposure, these labs worked wonders.