I think the point is: it's harder to do those things properly in PDF format. Also, I'm not sure how 'not designed for reading on screens' is subjective. PDFs

I think the point is: it's harder to do those things properly in PDF format. Also, I'm not sure how 'not designed for reading on screens' is subjective. PDFs are paper-document oriented and don't display well for reading on anything other than a large size monitor in virtually every case I've seen. When delivering content in a web browser, why on earth would someone prefer to view PDF vs a reasonably well laid out HTML version? I think PDFs are common in gov't websites because much of the internal culture is paper-document centred, and having those nicely printed PDFs solve internal problems for gov't employees, not because they are actually any better for the users of the website. Canadian Gov't websites are full of PDF content too. :(