I don't even think it offers a meaningful degree of security. It's a form of theater, you have to be hand-selected to perform the audit that Apple promised.

Most sysadmins know that hash matching only mitigates a small subset of rare upstream attacks. Apple could still be MITMing the whole thing (SSL added and removed here :)) and no auditor would get the chance to check. The offered audit is so weak that I would not trust any FAANG business to administrate it.

Apple is once again demanding arbitrary centralization to give them an undeserved veto power. None of this is for security.

If they're not "hand-selected", what would be the way to select the auditors?

Just have an open house for anyone interested to come poke the hardware and software?