Whenever anyone does anything, there is a reason and there is a REAL reason.
“There are other reasons why cards in slabs are removed,” explained Sue MacKay, director of Collections at the Hall of Fame Museum. “For instance, thicker slabs require more storage space, but the main reason we do it is we’re just not sure if the slabs might eventually damage the cards.”
The REAL reason they're doing this is storage space. Everything else is just made up so they sound like they know what they're doing.