Why Break Up Greatness?

So clearly the one line that has worked without question is the second line.  In seven games Bertuzzi has 9 points, Franzen has 5 goals in 6 games and Filppula has 6 points as well, but looks dangerous out there.  So what do you do when you have a line that's on fire?  Well according to Babcock, you break them up:

"We’re a much better team this year, there’s no question about it - much deeper," he said. "We like what we’re getting out of the Helm line. We think Filppula, Franzen and Bertuzzi - and I might break that line this week – have been fantastic; probably our best line."

I don't understand it and neither does Babcock:

"I don’t even know why you’d think about breaking them up, but you’re trying to get other people rolling."

I certainly wouldn't do that, but he's a Gold Medal winning coach.  I'm a ex-college goalie who's now a beer league all star.  Who are you going to trust on this one?