My daughter got a school-issued iPad last year (junior in high school) and in my opinion it only served to distract her from studies at home (due to the constant Twitter/Instagram/whatever checking), and watch Netflix in her room rather than in the family area.
In her opinion, it did nothing to improve her educational outcomes, and only served to provide another distraction to kids in her classes. Most teachers did not integrate it into lessons at all. Many kids would simply play games in class all day. This is in a middle-class, suburban U.S. high school. After reading Amanda Ripley's "The Smartest Kids in the World", I'm even more against them in schools.
With these devices, the schools are adding more burden to the parents to control the kids' access to the devices simply so that they can get their regular homework done.
Unfortunately, it seems the "oooohhh, shiny!" perspective seems to win out with schools rather than encouraging hard work.