This is a great sickness of the web: every website does custom styling on controls, and neglects all but the most primitive UIs. The result is a lowest common denominator: the web only really supports the click and the tap.

Consider the humble popup button: a native one can support mouse input, or arrow keys, or keyboard shortcuts, or type selection, or accessible interfaces. Take it a step further and support scripting.

But if your popup button is a div with an onClick, it won't support any of these. Even if you go the extra mile and reimplement all of them, the user won't even think to try it, because it's a "styled" snowflake. So the web sinks.

HTML is way easier because it does a hell of a lot less.