[dr0verride]

The fact that the component is made up of html, css and javascript instead of layout code, styling code and logic code seems irrelevant.

[kitsunesoba]

The difference boils down to feel and behavior. You can style web controls to look very close or identical to native controls, but they’re always going to feel “off” with issues like increased latency, wrong animation curves, and lack of support for system features (such as spring loaded dragging and drag and drop on macOS).