Ivan's comment starts the other issue: "What do I do next, after scanning?"
For my video-DVDs, I have those catalogued by Titles with date-of-movie and other details - but all of these are Content Details. Not disk details. I couldn't imagine doing data-entry for Batch, for Date Purchased, MID, etc. I couldn't imagine spending that much time doing that data entry - and if I wasn't going to do it for every disk, then why do it on any?
Because, if I scanned one in 4 years and saw it was deteriorating (as if I'd keep the scanned images, too, all catalogued and data-entered, as well), it would be nearly impossible for me to physically examine any substantial number of That Batch Burned On That Unit.
"So if I can't 'fix' the batch that may be failing because of a Scan, then, uh, why am I scanning?"
Katrina and others have pointed out, "Scanning occasional new batches with the same old drive, OR scanning old batches with a New Drive" might illustrate Better and Worse possibilities.
Of course, these reasonable arguments circle back to my original question - "Why would I trust an engineer to design a Good Scanning Drive when he can't design a Good Burning Drive?"