To its easier to describe than see.

The great riders (meaning the fastest ones) never look like they're fighting the bike. Instead, both rider and machine look effortless as they move along, even sprinters in full tilt.

Then there's the rest of us who look like a monkey taking indecent liberties with a football. There's herky-jerky movements, we're pedaling squares with tense shoulders and generally look like we're in a war of wills with our machine.

You want to be more the former than the latter.

Rocking hips make you look like the monkey.

As others have said, just because something does produce more power over short intervals does not make it more efficient. Yes, this novel hip rocking idea may work for you for 20 seconds or 20 minutes, but during a two hour bike ride you're going to be expending a whole lot more energy (with muscles that probably shouldn't be worked that hard) to accomplish the same goal.

Take it from someone who had a bad fit, got into some bad form habits and now has a lifelong chronic injury because of it, doing it different than 130 years of ad-hoc rider research doesn't necessarily mean its better.