iPads are great for certain purposes like the Osmo. They're a relative failure when it comes to typing up a book report or creating a group slide presentation.
Osmo, one of the best and most funded education software startups, doesn't even make Android versions.
Probably the higher up you get the less students are using "educational software" and more just common productivity programs and I'd suspect the gap between platforms fades away there for general purpose reports, presentations, etc.
Given that advanced CAD software nowadays run inside a browser, I think the chromebooks will work just fine even the higher up you go.
I think they did the right choice, in this context chromebooks are significantly better than tablets, phones or even "real" laptops.
Kits like Osmo are a great example of this.
https://www.playosmo.com/en/