A higher thrust rating, from the start of the take off roll to level at cruise allows you to reach more efficient, fuel saving cruise altitudes earlier thus saving fuel on a sector basis.
On flights pushing the maximum range of the Aircraft I fly I always use a full power take off and a climb to altitude using maximum continuous power which equates to climb power in the high 20's anyway.
It did make a difference in our time to climb and saved a few critical hundred pounds of fuel when they were most needed.