[dboreham]

When I say it was implemented, I mean at Netscape around 1999 we had projects with banks where they issued smart cards, used with USB readers, that facilitated SSL client cert auth. Similar to today's FIDO2/U2F. I don't know why these schemes were never widely adopted but it wasn't because the implementation was lacking.

[tatersolid]

I used these all these systems, and even helped run a smart card conference back then.

The implementations were very lacking. As unusable as PGP for normal people. The banking industry took a hard pass on the whole thing for good reason.