I read online that Google's Chromebook use SSD Flash memory, so their drives won't break as easily, and they are also fanless because they don't overheat because they run cool. All the files are also backed up to the internet, and the SSD drive, so losing files is not very likely.
They are cheap, so for the price of 1 Windows laptop which usually cost $500 or more dollars, a school can buy 5 or more Google Laptops, and according to https://sites.google.com/a/kcd.org/google/faq , Google is willing to extend the warranty up to 5 years, so they are pretty durable.