From what I recall (no longer involved with the school but I remember some of the preliminary discussions), the iPads are locked down so that inappropriate content can't be accessed, let alone downloaded. But even though the value of the iPads is diminished because they have been so tightly restricted, some of your concerns are the same as ones the teachers themselves had, which is why it has taken the school longer to roll it out than they'd initially anticipated.
But iirc, there were also savings to be made, eg on photocopying (which can cost schools a lot
).
But one of the things that the iPads do do is equalise access to education (so it's not just the middle class kids who get to use a computer at home). However, one of the things that the school identified was potentially lack of access to the internet at home - so therefore the inability to upload homework - so had to/is trying to work out ways for those pupils to have access (whether that is through extra library time at the school or elsewhere).
It's a modern day equivalent of ensuring access to books at home. There are households that have no books at home - which means that those kids are at an immediate disadvantage
In the modern world, understanding/being able to use tech is also a necessary skill.
It's a pilot, so it will be interesting to see the results.