While I agree with your statement, bear, if a gun I buy is materially misrepresented by the seller, I am certainly going to make every effort to return it to the seller. Starting the Form 4473 hampers this effort, not starting the Form 4473 removes one possible hurdle in the return process.
Case in point, I purchased a used Colt 1911, sale was stated as no returns or exchanges. When the weapon arrived, I discovered the barrel to be bulged. A quick phone call to the seller, with clear photos of the condition I found witnessed by my FFL, they agreed to make it right, but it involved returning the weapon to the seller, which, by the way, provided a return prepaid shipping label. Had I started the 4473, the gun would have had to have been transferred back to the seller, and transferred back to me again, upon return, costing me double the transfer fees. Had the gun I purchased used had a slight scratch on it or holster wear greater than I had expected, this, I don't see as a material misrepresentation. However, a 1911 with a bulged barrel is not usable as is. I would have pursued other remedies had the seller not agreed.