Eventually — and specifically for healthcare — yes! But I'm not sure if a citizen from one country can easily obtain credentials from another. It seems mostly meant for cases where you might need to sign on to a Dutch government website and you can then just use those Czech U2F tokens. It is a way forward though, but currently mostly hypothetical.

Unfortunately, while there is a migration going on from offering only DigiD to offering the whole eIDAS suite (in the Netherlands this is done via a government service called ToegangsVerleningsService, so vendors only have to implement a SAML connection to that which will eventually support eIDAS), it is by no means sure that every government function will allow eIDAS instead of just DigiD. It's honestly a very opaque process.

Great to hear that the Czech Republic chose U2F (now part of WebAuthn) though!