Energy inefficiency can't be good. That doesn't yet mean that efficiency alone is sufficient. Every economist worth his or her degree would conclude that we need a price on carbon or a similar instrument. Bonus fact: There's no direct rebound effect with pricing mechanisms.
Yes, the rebound effect is real. But it's also small. And what's there is actually positive! Why shouldn't people who can now afford to, due to more efficient energy technologies, be able to improve theirs lives?