Plastic comb bindings are incredibly popular for schools, especially K12 schools, because they are incredibly inexpensive, so you can get a lot of document binding completed, even within tight education budgets. They are used for student artwork collections, course catalogs, syllabus', and so much more. In addition to the affordable price, plastic comb spine bindings come in a large selection of colors, so you can easily match your school colors for perfect coordination and branding.
The spines can also be custom printed, whether with your school name or logo, or with the document title. Plus they come in a huge selection of capacities/sizes, so you can bind all of your thin documents, or thick ones with the largest 2" comb binder spine. The comb binding machines you see are popular for K12 schools, as they are easy to use, inexpensive, and meant for occasional binding volumes, rather than heavy-volume. When you bring your binding in-house, you reduce the costs previously spend outsourcing, eliminate the need to wait for someone else to bind, and allow for on-demand book binding for all your staff, teachers, and even students.