The 1.1.1.1 resolver also implements the latest privacy-enhancing standards such as DNS-over-TLS, DNS-over-HTTPS, QNAME minimization, and it removes the privacy-unfriendly EDNS Client Subnet extension. We’re also working on new standards to fix issues like http://dnscookie.com
Even from a practical standpoint, it’s become less and less relevant. It was badly designed, and poorly implemented. Modern CDNs have other ways to optimize routing, and if the actual client IP is needed, XPF does a better job.