It's relevant b/c it gives people an actual spectrum of choices to choose from that may fall more directly in line with their politics, versus making people box themselves in and basically join the bloods or the crips. So many people who vote now for the two main parties don't adhere to more than 50% of what their party's platform is, but they vote for them because of the "me versus you" aspect. It's just another source of division and diversion, IMO.
Fwiw, I don't care about platforms anyway, because they get largely ignored once a candidate takes office. When voting for a candidate, I tend to look at that candidates style of leadership and what he or she has done in the past. I support Romney primarily because he showed a history of being able to work with the other side.
IMO, the biggest problem with politics in our government today is that to many individuals do adhere to their beliefs to the point that compromise is becoming impossible. And in our style of government, compromise is a requirement unless one party grabs complete power (which rarely happens). And if we had a third party, complete control would be even more difficult, making compromise even more necessary and yet perhaps more difficult to attain.