They don’t do this for sneaky reasons – it’s just how they work these days.
But that does not minimize the privacy issue. In secure settings, it is common practice to remove and destroy the hard drives from any copiers or printers which leave the site.
Copiers in days of yore – scan an image onto a drum, roll the drum over paper, you get a copy.
Copiers today – the copier is a combined scanner, printer, computer. Scan to disk. Manipulate the image – enlarge/shrink/rotate/re-order pages/print double-sided/whatever…
THEN print to paper.