I actually use Outlook as an RSS reader. It's not very good but it works and that way everything is in one place.
Also, I think Outlook is much better than any other mail/calendar client I've ever used.
I read HN, Reuters, Re/Code, Atlantic and New Yorker in Outlook. I love the mostly text-only experience and am finding that I read content in a less prejudiced way when all the color distraction is gone.
No, "everybody" uses Outlook because corporate IT likes how all the microsoft stuff integrates with itself.
Everybody also apparently uses their phones for email now, which I understand tends to use installed apps rather than the web browser.
[1] Yes, person who is about to reply, I know you personally didn't.
Right, ignore and marginalize all the people who have counterexamples to your claims.