Vacuum sealing sounds good but I would consider two potential pitfalls. First, the plastic could emit gasses harmful to the books or cause a chemical reaction with the paper, ink chemicals, or the inherent acidity of the paper. Secondly, most paper products need to have some level of humidity to prevent them from becoming too dry.
SW or bags allows for this gas/moisture transfer.
Cost would also be a consideration. Have you figured out what the estimated cost is per book and compared it to
SW or a standard bag and board?
Interesting approach though. I'd be curious to see the long-term results. It certainly wouldn't allow additional contaminants to get in such as mold spores. Of course, if they were already present it won't help, except to render them inactive since most molds needs oxygen. At least you will get some additional use out of your machine!