[w3ll_w3ll_w3ll]

In Italy we have SPID https://www.spid.gov.it/en/ I believe it is similar to login.gov in US.

[lxgr]

Is that used by any private companies at all, i.e. can you open bank accounts or other sensitive private accounts with it?

login.gov is unfortunately only accepted by government services, and as far as I can tell only federal ones too – at least NY state has their own thing... (NY.GOV ID)