Rules and Regulations
It's been many decades since I worked on a US government proposal. But back in the day, even the most modest proposal had to be delivered in physical form to a specific place by a specific time. If any portion was classified it would have had to be handled according to appropriate rules -- double wrapped, properly marked on the inner wrapper, delivered by hand or registered mail, hand receipted so that a security audit of the submitter could establish where the numbered copy went. And it would have had to be accompanied by half an inch of properly completed forms attesting that if granted the contract the submitter would fully comply with thousands of health, safety, workplace policy regulations; wouldn't discriminate in employment, wouldn't pollute the environment, would use no product produced in Cuba or North Korea, etc,etc,etc.
DVD sounds to me like a step forward.