

Wide display: perfect for reading A4 documents
keyboard: nicer to type. Also, the passport was as wide as, well … , a passport so it is a pretty decently sized keyboard which isn’t comparable to the tiny Q10.
The passport was never meant to be a generic for the masses device. It is a beautiful specialized tool.
Not really. 2FA or other “strong” authentification for requesting the auth-code is common.
The receiving registrar doesn’t care at all.
Likely the only check there is, is fraud protection and that is them protecting themself against payment frauds and not you/the domain.