A Raspberry Pi is a tiny little computer. A lot of people think that it's the next big thing in programming and in a way they would be right, but not in the sense a lot of people originally thought. Let's be honest Linux runs on just about any PC going and quite a lot of other devices too. So you probably wouldn't want to get a Raspberry Pi just to play with Python or Linux when there's probably a perfectly good PC on your desk?
However think of the cost of the Raspberry Pi! You could attach it to any TV and it costs less than a decent set of headphones. You can now afford to put a computer into virtually any Design and Technology project you fancy. It'll turn any flat-screen TV into a media server in a few seconds, it could easily be wired up to sensors and the maintain a web page for you, it could be put inside an arcade cabinet, used to show students networks and control robots.
The point is that the Raspberry Pi brings us back to where we can see the chips and the interfaces and that's what has been missing in the last 10 years in IT!