My understanding is, the lower the thrust for takeoff(within some particular limit I suppose) the lower the engine wear. The higher the climb thrust, the shorter the time to reach cruise altitude which reduces overall fuel burn.
As a comparison, I was told(so it may not be true) by an F-15 pilot that using afterburner to go straight up to cruise altitude was a more efficient profile than a normal cruise climb. To be confirmed by those in the know.