In the world of coin collecting, older third-party slabs have become collectible themselves.
Collectors keep loving slabs. Third-party grading has brought enhanced transparency, liquidity and confidence to the rare coin market. Perhaps in recognition of this, collectors covet rare encapsulations from grading firms, especially Professional Coin Grading Service and Numismatic Guaranty Corp., and these unusual slabs have become collectibles in their own rights.
Complete article:
How coin holders have become collectibles, Coin World, 10/25/16.