[WayneDB]

Keyboard acceleration. I have never seen an HTML control kit that handles the Tab or Arrow keys correctly or even very well.

No standards. For example - Drag and Drop. There is no standard system for Drag and Drop between components in the browser because it doesn't know about these controls, it only knows div div div div div. So, in general - it's just harder to write good code that targets HTML components because there are no standards for complex components.

(Some more patterns with no standards for complex components: Data Binding, Encapsulation (grouping one or more component into a parent component and walking parent/child components), Inheritance.)

And then, there's performance. Native trumps HTML here, no contest.