Flash is evil. Not. While I agree that Flash used badly is bad, but that’s true of every technology. Saying flash makes “the Web much less usable” is like saying the Web makes FTP much less usable. We’re extending the media, folks.
The web enables you to view all those files intermingled in one screen, whereas FTP forced you to download documents then use them. As the web was extended to include interactivity, it only makes sense that would eventually include animation and rich media. Sure you have to install a plug in, just as you had to install a web browser, just as you had to buy or seek out a computer. It is another hurdle, but it’s worth jumping in some cases.