A standard flatbed scanner is great for paper, and maybe very thin books that open flat. However, the thicker the book the greater the problems:
1) You cannot get the pages flat without breaking the binding; hence, text near the binding edge up to 2 inches is shadowed and even completely obscured.
2) If the book is thick enough, the top to the scanner cannot go down far enough, and the image is compromised by light leaking in from the environment. It's somewhat akin to xeroxing a page with the lid up.
3) The mechanical components of scanner itself can be damaged if too many thick books are scanned. I've seen too many scanners with the lids broken because of this. By broken, they won't close down for anything. Repair isn't cheap if it can be fixed even.
So, if you're planning on scanning a bunch of books, get a scanner suited to the job.