The point of an OSS printer isn't just for cheap supplies. I'd love to hook a printer up to an email server so that I could send it PDFs and it would just print. If I had an OSS all-in-one printer, I'd probably hack the scanner to email me PDFs of documents that I scan from the ADF.
> I'd love to hook a printer up to an email server so that I could send it PDFs and it would just print.
I did that in the 1990s, except I would send it PostScript files. IIRC the printer I used was some Epson dot-matrix fan-fold thingy, but I could have used anything supported by GhostScript.
There's nothing to stop you trivially scripting either of these. I expect Thunderbird or Mail can run scripts on incoming email, so you could have a printing, archiving, grepping, forwarding email account, if you liked.