Now I am totally confused. I have always been told that a BEAM reach is the fastest point of sail in terms of pure speed. Isn't that what they do for all the record speed runs? And they don't use spinnakers, of course. If a boat could go faster on a broad reach with a spinnaker, why wouldn't they be doing that to set records?

For sailing to a downwind destination, and tacking downwind, a spinnaker might get you to your destination faster, but it is not because the boat is going as fast as it can go.

Am I wrong?