I use a different model portable scanner, a
VuPoint Magic Wand. (Note, there is a newer model out, with Bluetooth.)
You do need to have books with a decent margin, minimum 1/2", better is 5/8" or more. If you do have the requisite margin, books can be scanned without cutting them. It will help if the book is not overly thick.
It helps to use a piece of black card stock under the page you are scanning, and it is also a good idea to use a stack of magazines or catalogs to support the card stock so you get a smooth roll off the page. This is going to make scanning a bit slower than using a flatbed scanner. The plus to the portable scanner is that I can scan books on my coffee table while watching TV. I get good scans that OCR nicely with my little wand scanner. I think the VuPoint is cheaper as well. I found mine on eBay for $54 shipped.
A downside is that the VuPoint is not that great for illustrations. It's passable, but will introduce some scan lines. At any rate, my VuPoint is serving my modest needs well. And most of the books I am scanning do have the needed margins. Some, of course, I will have to cut if I wish to scan. Others, if they are valuable, I'll use a camera on. Anyway, a little portable scanner can work, it's all in what kind of stuff you need to scan and what your needs are.