You don't want to type URLs, especially on mobile, but the fact that all the items on the home page of HN are links to web pages and not to screens inside apps should hint to a definitive advantage of the web over apps. And to why having a web site is mandatory and having an app is optional.

If the web and apps where in the same competition I'd say the Web can't lose, but I don't believe they compete. They serve different purposes with some overlaps (think Google Docs, the web site and the apps).