That being said, I believe he is all wrong regarding hybrid mobile development
Ultimately, and this is a mobile only problem, hybrid apps are much harder to debug than native ones. Safari just recently introduced a debug bridge that supports attaching to a running web view. On the Android side this is also possible with Chrome, but only for Android 4.4 and higher. When chasing complex defects this can be a nightmare, so your code better be good and nicely structured.