There is a point here that many websites don't need an app, but have them as part of a fad.
However, on the flip side as wearable tech becomes more and more prevalent (think Google Glass, but also things like Jawbone), it make a lot of sense that more and more of our internet usage goes via these interfaces which are inherently non-web.
I've coded for google glass, and I don't think our internet usage will go via wearable things -- at least not ones like glass.
Information displayed needs to be understandable at a glance and relevant to the very here and now. Usable real estate is extremely limited in glass and interaction is limited to voice, simple gestures against the right frame, and GPS/accelerometer. So doing interaction with any amount of complexity gets frustrating and annoying very quickly.
However, on the flip side as wearable tech becomes more and more prevalent (think Google Glass, but also things like Jawbone), it make a lot of sense that more and more of our internet usage goes via these interfaces which are inherently non-web.