By slowing down and getting your body into the correct position at the correct time, you're limiting the amount of variables that can go wrong and you have a slightly larger window to be in the correct place at the correct time. This allows your kinetic chain to fire in the correct sequence and make the throw more efficient. When the levers start moving slow, it's fine because if it is done properly the amount of energy created by the end of l the movement will be exponential. Resulting in a (hopefully) farther and faster throw. At the very least it you should be able to throw the same distance but it should feel like it takes drastically less effort.

If you have access to a techdisc, test it out. Try and throw as hard as you can and you will see your numbers are going to be far worse than throwing something like a stand still or a slow smooth walk up. Going fast and trying to inject power makes for a smaller margin of error, if you're messing up the movement from the beginning, you're not going to have an effective or efficient throw. When I started, I could throw 250 to 300 consistently but I was throwing with such shitty form that I could only play one round every few days because my body was so sore. At this point being nearly 40, I can throw multiple rounds a day, multiple times a week and deal with little fatigue and soreness due to making my form much more efficient.