Web developers care, because we know that, despite our best efforts to the contrary, IE for Windows is what nearly everyone is using. Less frequent (and less widely available) improvements to that product means we'll be stuck supporting the current version for the foreseeable future. While it's a far better lowest common denominator than NS 4 was, it still means that most folks won't be seeing full PNG support and support for advanced contextual selectors in CSS until who-knows-when.
I'm assuming that it's cos of the anti-trust case
On the contrary, this seems to fly in the face of the anti-trust rulings. It was bundling IE with Windows that got them into trouble in the first place. Now, they're making it available only as a bundled product.
Personally, I think that part of their motivation is to convince everyone that IE is truly inextricable from Windows. Of course, anyone with a technical bone in his or her body knows that's a load of crap.