I think it's more likely the JPEG blocks which straddle the box edges simply don't cover any meaningful part of the text. 12 pt font at 96 DPI is 16 pixels tall, meaning 50% of the vertical height of a line simply wouldn't fall into the blocks straddling the edges of a line-height box. You'd get ascenders and descenders but not much else. Tops of numbers or all-caps I think is best case.
Though, web images now are being served in higher resolutions (200+ DPI) for "retina" displays, and scanned images are generally 300 DPI, in which case you'd be lucky even to get ascenders and descenders.
I'd be curious to give it a try though. If Facebook memes are any indication, many humans are totally oblivious to near-unreadable levels of artifacting.
Though, web images now are being served in higher resolutions (200+ DPI) for "retina" displays, and scanned images are generally 300 DPI, in which case you'd be lucky even to get ascenders and descenders.
I'd be curious to give it a try though. If Facebook memes are any indication, many humans are totally oblivious to near-unreadable levels of artifacting.