This is of course useless to me, and to any other developer who prefers to use standard tooling rather than proprietary lock-in stuff.
I don't begrudge Microsoft shipping a GH CLI as an optional thing, but shifting workflows away from the standard client is one of those changes that doesn't serve users, but rather serves some PM's KPIs.
EDIT: based on the "not on my machine" responses here, it's clear that I'm on some branch of an A/B test. These are the only three options now presented in my GH web UI - all the rest have disappeared (https://imgur.com/P7llsVo):
1. Checkout with the GitHub CLI
2. Checkout with GitHub Desktop
3. An ad for buying Codespaces for this public repo