Sure, you will not die if your music skips or your browser stops responding, but it's annoying. For example, while you're using Eclipse and it is randomly kicking off builds or doing gwt compiles, you're also using your computer to stream music or perform research in a browser window (for example, researching the cause of a build problem). Let's also say that while you're working on this application, you have a bunch of other applications that have modest cpu requirements, but are essentially real-time applications. Let's say you have a multi-threaded application that tends to either be idle or aggressively grabbing 100% of every CPU for several minutes, doing searches, builds, etc. This is a very useful feature in certain scenarios.
