It is not about a ui pretending to look native. It is more about form interaction patterns that users are subconsciously habituated to. For example: - Pressin

It is not about a ui pretending to look native. It is more about form interaction patterns that users are subconsciously habituated to. For example: - Pressing enter submits a form. - Clicking on a label focusses the input box. - In OS X readline style shortcuts are available in all input boxes, eg. Ctrl+a takes you to beginning to line, Ctrl+e takes you to the end etc. When these things don't behave the way you expect them to, it really destroys the user experience. Building on browser runtime gives a lot of these platform specific accessibility features to you for free - which may not be very trivial to arrive at through cross platform native gui libraries.