I'm pretty sure it does but maybe I'm wrong, I had never tried to create popovers/popups using CSS. What's neat[†] about the popovers API is that it doesn't need any JS, you just write a couple of HTML attributes and voila, a popover/popup. They will run with JS disabled as well.
This doesn't look like it gives websites something they couldn't do before with CSS and JS.
I'm pretty sure it does but maybe I'm wrong, I had never tried to create popovers/popups using CSS. What's neat[†] about the popovers API is that it doesn't need any JS, you just write a couple of HTML attributes and voila, a popover/popup. They will run with JS disabled as well.
https://chrisburnell.com/html-can-do-that/
[†] Neat for me building things like tooltips and dropdowns into my web apps without using JS; not neat for annoying people with popups.