Ha, now even Google leaks such secrets :) Trust no one :)
But on a serious note, this is the best entrance when there are crowds at the pyramid. The only drawback is that you land at the end of a wing, so there is a lot of walking to do to reach the Egyptian or Middle Ages section for instance. There are great paintings on the way, though.
I cannot talk about the secret entrance at the Lions Gate because it would not be secret anymore.