I don't understand the hate for this trick. It still breaks cross-site user tracking. It's just sort of a hack around installing a hypothetical Google Analytics app on-prem or pumping in data via a server-to-server integration.

Google Analytics can't cross-reference data from other sites on the browser, b/c it's not a third party cookie now... what's the problem?

Work is ongoing on that front too: ttps://webkit.org/blog/8146/protecting-against-hsts-abuse/