Maybe somebody can do a better job of boiling this down than I can.
Basically, right now, if you ask for something on the internet, it gets served to you. Sure there are lots of server side protections that may require an account to log in to access things or what have you, but still you can at least request something from a server and get some sort of response in return.
What this does is force attestation through a third party. I can ask for something from a server and the server turns to the attester and goes, “Hey, should I give this guy what he’s asking for?” and the attester can say “No” for whatever reasons it might. Or worse yet, I can get the attestation but the server can then decide based in turn that it doesn’t like me having that attestation and I get nothing.
You can make arguments that this would be good and useful, but it’s so easy to see how this could go sideways and nobody with any sense should be taking Google or any of these large corporations at their word.