Why? If I were able to travel I'd much rather go to Vegas than San Diego. Once you're not in the BCS bowls all it becomes is a reminder of how a playoff system is necessary.
They'll go to the Vegas because the Holiday bowl will take USC or Arizona and the Emerald bowl will get to choose between Cal/Stanford. At least they'll get to maybe make some connections in their old recruiting grounds in Vegas.
What should they have gotten the Holiday Bowl? Arizona deserved it more than them. Arizona beat both Oregon State and Stanford. They should have gone to the Sun Bowl but they claimed their "no-repeat clause" and took Stanford. Isn't that the home team anyway? After the Rose Bowl does it matter what bowl it is? The Pac-10 has crappy bowl tie-ins so it really doesn't matter if it's the Holiday Bowl or the Vegas Bowl.