I'm not a spin boat sailor, so I won't claim first-hand knowledge, but that makes sense based on conversations and observations.

Running the spin makes you faster and somewhat minimizes the effect of the breeze, as the apparent wind moves forward.

Dealing with frequent 10 knot gusts when you're already depowered due to high average wind is what really wipes you out. True on any boat, even more so with a ton on sail area up.

Mike