Those that will choose to show ads and track users will at least invested time and resources into optimizing their code, leading to faster-loading and smoother sites.
Work on this experiment began this past week, according to a WebKit Bugzilla entry, so this isn't a feature users can test right now. Weeks, or even months, of development are still needed.
With the EU Cookie Law, GDPR compliance requirements, newsletter subscription forms, the Web Notifications API, and browser permissions, users have just had enough of popups for the time being.
All the Chromium-based browsers
More browser coverage: