Yeah, great point…Aerojacket wheel covers from Wheel Builder are a great, low-cost alternative to a full disc. Almost all of the aero benefits at a fraction of the cost. I raced numerous 70.3 and a full IM on one.
I eventually bought a Zipp disc wheel literally because I wanted the “whomp”. 
Found a good deal on a used PowerTap version and dropped the $$ on it out of vanity. 