That is a way to throw a disc fairly far, I don't deny that. Again I am a layman, but did take this out to the field today to apply it to throwing discs. There is a big difference in how it feels, one of them seems to be:
If you open early, you are starting your acceleration before it truly matters, which idealy is in the power pocket or MUCH closer to it. You are pulling your arm from the backswing WAY to fast from the start doing it this way, there is no room or stored leverage for acceleration at the end. If you delay the acceleration until the brace, and have pulled the disc into the pocket, THEN explode, the acceleration makes a huge difference. It is also much easier to control and think about the movement as a whole, even on day one for me.