The answer is "maybe". Increased tempo and momentum means increased energy available to put into the ball. But it's not a guarantee that extra energy will get put into the ball. You must have good mechanics and timing to ensure the energy is transferred eficiently through the body - up the kinetic chain - and isn't wasted somewhere.
However, increasing your tempo also has the added benefit of helping out with your timing. Specifically, it takes away extra time in your delivery - time during which you might do something wrong like opening up early. It also makes you quicker to the plate and allows your mechanics from the wind-up and stretch to become more similar which is a good thing.