> It's almost indistinguishable from a native Android app. If I put a little more effort into the animations it would be even closer.

The key phrases here are "almost" and "If I put a little more effort". The almost-but-not-quite-native webapps are the mobile ecosystem's equivalent of the uncanny valley. It sort of looks like an app, but then it suddenly 404s a button, or starts lagging, or doesn't do the default for native controls, but rarely used function. It's enough to break user's trust in what the app is and what it's doing. It feels like Java's Swing all over again.