Throughout my time as a high school coach I have gone back on forth on the value of a "playbook". I have talked to a lot of successful high school coaches and they do not have a paper or a digital copy of their playbook, but they have their players write down the plays and install the plays using walk - thrus. I like this philosophy because you want your players to have to process the information and not have it given to them. Plus, most high school players will not look at their playbook, and if you want to make tweaks to your coverages, blitzes, fronts, etc., you have to tell the kids to not look at their playbook and retain what you are teaching them.
As an offensive lineman at Liberty University I never received a playbook, but our coach gave us a notebook and a pen to write down our schemes / fundamentals. I have kept those notebooks and it is really cool to see the gameplans and the tweaks we used during the season. By giving us a notebook and making us write it down, it forced us to take ownership of our learning and we could put it in a format that made sense to us.
Kliff Kingsbury doesn't use a playbook and he is one of the top coaches in all of college football. He makes his players write down their assignments and they use walk - thrus to SHOW their players the plays. I have always believed that "doing is learning", so why not transfer that to the football field. It is a fact that you remember a large amount of what you write down, and you remember even more of what you physically do.