By shifting towards a purely "open" software stack, schools then have the ability to purchase older, cheaper hardware. Instead of running bloated spyware (Windows) IT departments could opt to use any one of the lightweight Linux distros available.
This would reduce e-waste, save school districts significant amounts of money (no need to purchase Windows licenses or beefy hardware to be able to even _run_ the operating system) all while still maintaining a high level of user/network security.
Heck, you could even have a fleet of Raspberry Pi devices as your main student "computers". The cost of replacement also becomes less significant (these are children using these devices remember).