Accurately is a misleading word. It depends on what your goals are. Maybe you prefer to make a bit less profit so that people can read more, as a public service. Or maybe you're just using those books to attract people into the store.
Finally, the scanners don't know if you can price "accurately", so if you can, they're just occupying space and blocking ways for no benefit to anyone.
All thrift stores I know of and have donated to exist to raise money for a charity. They should be thrilled to move stock. But the vast majority of books are next to worthless, so your "read more" crowd will have plenty of options, and won't care that some rare first edition got picked up for premium pricing.
If scanners don't find anything to resell (because you've already scanned and correctly priced, or even listed online yourself), they'll leave soon enough.
Finally, the scanners don't know if you can price "accurately", so if you can, they're just occupying space and blocking ways for no benefit to anyone.