I can speak for the countries I've lived in. In Spain they use regular digital certificates since ages, in Italy they've recently introduced a weird cloud system. In the UK it's username and password (+ 2FA).
>Italy they've recently introduced a weird cloud system
Not really weird in itself, but overall stupid, what is weird is how you get it (and how its use is becoming mandatory almost anywhere in governement sites).
The thingy is called SPID, and you get it through a small number of (private) firms (for a fee) or from Poste Italiane (the National Post Office) for free.
What they don't tell you (and that you learn only once you have one) is that there are three levels for it:
1) lowest level basically login+password
2) middle level, login+password+SMS or 2FA via app
3) high level that requires a smartcard (like the new electronic national ID card or the Codice Fiscale card) AND a smart card reader
BUT on some government sites (not all) you can use any among login+pin/password, SPID, CIE or CNS.
It is a mess.
Of course banks do not use any opf them and you have separate login+password+SMS or 2FA via specific bank app.
