@izzythepush,
Ok, I finally read the full article. This discovery isn't so much about proving gravitational waves, they seem to be taking that in stride. It's more about confirming the Grand Unified Theory's version of Inflation. And that would be big.
If GUT Inflation could be confirmed then it would eliminate a whole swath of other theories which were clouding (and pulling intellectual resources away from) GUT study.
They would still have to figure out how Gravity fits into the theory, but this would be one giant step closer.