And also because people who characterize NNTP as "widely known" or "well supported" haven't taken a good look around in the past decade. There are very, very, very few clients left for Mac or Windows that are actively supported (and they're mostly all shareware or commercialware) and if you asked 100 DW users what NNTP was or if they'd ever heard of a newsreader, you'd get 1 "yes" and it'd be someone who's still reading Usenet with their old copy of tin.

(I mean, I love tin. But the Average User can't run tin.)