I suspect the author, like nearly all of us here will get more exposure to BPA from handling supermarket (etc.) receipts than from this gimmick.
Thermal paper was widely used for fax machines and portable printers years back as well.
Fun fact: when Apple first opened retail stores, they printed receipts on big Lexmark laser printers, 8.5x11, on VERY nice paper, like resume paper, it was absurd how nice and thick the paper was. It was preprinted with return policies etc on the back (and maybe a color Apple on the front?) It only lasted a few years like that and they eventually got cheap thermal printers installed.