America’s Cup boats have rigid sails and they go pretty damn fast…and while you may not be able to orient a disc ideally relative to the wind to achieve maximum benefit, it doesn’t mean there still isn’t a sub-optimal benefit to it.
We seem to be getting tangled up in terms…call it whatever you want, but the net result is that the higher the yaw, the more aerodynamic benefit a disc wheel provides. The data bears that out.