I'm not sure that it would let you lower the peak power. Most takeoffs aren't limited by runway length. You use full power just because it's safer to get off the ground earlier. Max power requirements come from the maximum altitude the plane is expected to reach, or for multi-engine aircraft the need to be able to climb out after an engine failure.

Aircraft carriers (some of them) use catapults because that's a case where runway length is, by far, the limiting factor.