I would imagine that if 50 people got the same junk mail flyer they have a system that only scans the flyer once as there would be no need to have a scan of the specific piece of junk you received. Otherwise yes it seems weirdly cheap.

Right. The economics just don't make sense, and I'd be shocked if they were still in business in 2 years (unless they sold your private data.)

This would only work efficiently if it were part of the USPS.