I actually use Acrobat to routinely compress the files I get back from Bookscan.us (I dropped my 1DS membership after a while). The size difference is astounding: some compressed books end up being 20% the size of the original scan. There is a time cost of course: my Core-i3 laptop can take many minutes to compress each file.
I have a lot of textbooks and the original color scan might result in a 500MB file - saving this file as "Reduced Size PDF" will often result in a 120MB file. For black-and-white-only scans (offered by Bookscan.us), a 40MB fiction book might be reduced to 15MB using the above trick. Thus, this Acrobat Pro feature has really helped me: my collection (in reduced size form) is currently at 13GB; without compression, I would probably have found a 64GB microsd card a tight fit. I personally found Bookscan.us's OCR adequate when I do my spot checks: I have used Adobe's OCR a few times on other documents but it takes way too long to run so I find the time penalty for the non-discernable improvement not valuable.