Not a bad idea, and I used to save lots of web pages as PDFs in the distant past, but I've noticed that a large percentage of sites will not print out correctly as a PDF these days. I see myriad problems these days: the page is truncated on the right (no matter how much you zoom out), or all pages come out blank after the first page, or the PDF gets rendered as an image (taking many megabytes per page) rather than as text, or the outer frame prints but inner frames with the actual content are missing.

The more "modern" the site, the worse it is. Surprisingly, government websites often print correctly since they've done the least amount of work to make the site modern looking.