It should have been Valve doing it! (And that comes from someone hating on Epic and loving Valve, BTW.)

I've written at length elsewhere in the topic about how it's not just the technical implementation, but what this attestation process signifies about control of these companies over your system.

I understand this is one of the weaker arguments I can make in isolation, but it bears asking the question: why is it Epic that's doing it and not Valve?