1.) I grew up in a poor area. For high school they introduced an alternative school where you could come in whenever-- basically just rooms full of computers, you would take the whole lesson on the computer. They were able to use only a few teachers for a lot of students this way. While the courses themselves could use a little more work, overall it allowed people to finish high school that otherwise wouldn't have. I think the "let the computer do a lot of the teaching" method is a great one. Lets people work at their own pace and takes some pressure off the teachers.
2.) In an ideal world I would think you could buy a laptop and then save money on books, but at least here in the USA I don't usually see it done that way.
3.) Even if they're doing totally irrelevant stuff, knowing how to use a computer to search for answers and filter out bad information is a great skill to have. So while yes, they need to do their homework, I don't think it's awful if they also use it for playing on.