And a good question. With respect to my statement, the answer is "Because I said so" as my father used to say. Sorry. There have been numerous tests done over the years.

A disc in the front and rear is actually the best. This is universally accepted based on data from testing - a disc wheel is unbeatable. However, a disc in the front isnt possible for control reasons.

Enter the Hed 3. It has a deep rim (60mm-70mm ish I think) and aero "spokes". There is no spoked wheel that can be used on the front that is as aero as the hed 3, without being to deep to be safe and controllable. If you search for a while, you can find several of these studies and reports. I have seen several, but I dont keep track of them. Analytical cycling is a good place to start (google it). There are yaw angles where the Hed 3 can be beat by a spoked wheel, so the arguement is not universal, but in straight-on and low winds, it is the reference.

Within these arguements, there are sub arguments stemming from lenticular shapes and dimples, etc. These claims are probably true, IMO. They make sense from a physics standpoint, but they have not really undergone the test of time to see for sure.

In that regard, there isnt really a 1 right answer in the area of aerodynamics. It depends on a variety of things. For instance, a wheel may in theory be better than another, and on most frames, will be in real life tunnel testing. However, on a certain bike, the air turbulence may interact with the frame or fork of the bike that makes that one particular combination an erroneous data point (This is just an arbitrary example). This is also why there is no "perfect" bike fit or aero-position. Only a guidline that will get you close.

In like manner, the same is true for aero. Deeper is better (therefore disk is best). Hed 3 is generally better, due to the benefit of the Hed 3 "spokes" vs regular or bladed spokes, even vs deeper non-disc rims.