Well, reason 9 of many:

Attempt to find the story you wanted to read using a layout and information architecture that’s completely different from the layout and information architecture of the website that you’ve grown familiar with, because some arsehole decided that the process of reading the electronic equivalent of a newspaper needs to be “disrupted” because he’s been reading far too much Seth Godin or some other bullshit.

There’s room for news apps out there – but his very final point is the killer:

Apps ought to provide some actual functionality, not just blobs of content wrapped up in binary files.