Faster speeds mean faster rendering time. As an amateur videographer, I need the Mac Pro to actually have fun with terabytes of footage that is accumulating and not to have to wait around all the time for things to render. Other machines can't hold all the footage and require tons of waiting time when you start learning editing. This can apply to home videos as much as professional edits. It's also nice to have a megafast machine with tons of storage space for all your home media files.
Non-pro home users have good reason to have a high-powered tower as their media base, from which they can operate their Apple ecosystem. With the right sort of marketing, Apple could convince every homeowner that he or she needs a 16-core hub to manage their household, along with all their iToys, in a post-PC world.
Maybe Tim has his spam filter on overdrive and Apple isn't getting enough product feedback on the Mac Pro.
http://www.apple.com/feedback/