Power conservation, multithreaded apps and multitasking are interesting, but not dazzling. Running two operating systems at the same time however, on a phone, is amazing. The device, built to look like a phone only about ten times larger, had a TI OMAP 4 Cortex A9 architecture chip and it was running Android 2.3 and Ubuntu 10.04 simultaneously.
Now, in reality, no one would want to run two operating systems on their phone at the same time. The only multitasking the vast majority of people care about is using their phone while simultaneously driving. This demo though does point out the power of SMP processing.
Power consumption should be lower for equivalent performance. For a lot of apps, it may not make a big difference - after all, you can only read email and Twitter feeds so fast. For web browsing, video and games though, the different should be noticeable.
Dual-core is just the beginning. The article notes that Nvidia is working on quad-core processors that should ship in tablets this fall and in smartphones by the holiday season.