Traditional developers often struggle with Mobile Apps why?
They are not used to having to manage tight memory footprints.
They are not used to having predefined user expectations for the experience - even mobile developers often getting this wrong trying to impose an iOS look and feel on an Android App.
They usually don't have to care about how much battery they use.
They live in a connected world whereas apps live in a possibly disconnected one.
We understand all the above - we know how to make apps tick.