German implementer here. We have to use some kind of attestation mechanism per the eIDAS implementing acts. That doesn't work without operating system support. The initial limitation to Google/Android is not great, we know that, and we have support for other OSs on our list (like, e.g., GrapheneOS). It is simply a matter of where we focus our energy at the moment, not that we don't see the issues.
> We have to use some kind of attestation mechanism per the eIDAS implementing acts.
What does this attestation need to prove? Is this only about ensuring that private keys are managed by a secure enclave or a TPM?
> we have support for other OSs on our list (like, e.g., GrapheneOS)
I appreciate that, even though I am really not enthusiastic of eIDAS. But time will tell. Thank you.