"... so you can use it today."

What if he wanted to use it for requesting blog.cloudflare.com

   ;; ANSWER SECTION:
   blog.cloudflare.com. 300 IN HTTPS 1 . alpn="h3,h2" ipv4hint=104.18.28.7,104.18.29.7 ipv6hint=2606:4700::6812:1c07,2606:4700::6812:1d07

Where are the ECH keys

For example,

   ;; ANSWER SECTION:
   test.defo.ie. 300 IN HTTPS 1 . ech="AEb+DQBCqQAgACBlm7cfDx/gKuUAwRTe+Y9MExbIyuLpLcgTORIdi69uewAEAAEAAQATcHVibGljLnRlc3QuZGVmby5pZQAA"

or

   ;; ANSWER SECTION:
   cloudflare-ech.com. 300 IN HTTPS 1 . alpn="h3,h2" ipv4hint=104.18.10.118,104.18.11.118 ech="AEX+DQBBpQAgACB/RU5hAC5mXe3uOZtNY58Bc8UU1cd4QBxQzqirMlWZeQAEAAEAAQASY2xvdWRmbGFyZS1lY2guY29tAAA=" ipv6hint=2606:4700::6812:a76,2606:4700::6812:b76

It's true one can "use it today". One could use it for the past several years as well. The software has been around for a while

But ECH has never been consistently enabled for the general public beyond a small number of test sites that are only for testing ECH