Bam! This. A friend of mine has a copper x-men, 200-something, that is labeled 9.0 but is faded and shriveled looking in the sealed case. CGC did not blow the call; an LCS hung it with window exposure for faaaar too long. He bought it for laughs, curiousity, a reminder that slabs still need care. The big difference that some fear, I suspect, is not knowing that the book was left in the Mylar. Odds are good of course that if it is, its in the same condition as when it's inserted. My mylar'ed books are. But yes handling mistakes can occur. I'm all for the extra protection of slabs for super-valuable stuff but I would be kind of sad to have an ENTIRE collection of books I could not read.
As as to the new service, I'm not much interested but not upset. It's a big world, there's room.