German ID cards also support eID functionality on their citizen ID cards and even permanent resident ID cards, but ironically EU citizens are qualified for the issuance of neither, so they had to introduce another type of card for them to not run afoul of EU anti-discrimination laws.

All of this is currently pretty messy and there's only limited practical cross-country acceptance of eIDAS signatures, but is supposed to get unified under the banner of EUDI (EU Digital Identity) "wallets".

Portuguese IDs also have a sim card, but I never used it for anything other than accessing government services.

in my case Spain with the DNI 3.0 but as others commented its a thing in many of them

has been the case for Hungarian ID cards for a decade now, but it was never really used, except maybe by burorats in gov offices to access their systems.

but no one understands it, including the people who need to issue new signing keys.

it didn't get anywhere really. it was just a good opportunity for a lot of taxpayer money to... "lose its taxpayer money nature" (actual phrase by an actual politician when cornered by questions).

and now they are "moving on" to an app that must be installed on your phone to access more and more services.

ID2030 is roaring on worldwide... soon mandatory iris scans, vaccine implants, and who knows when they will try to roll out mandatory brain implants against thought crimes.

the more i think about the sign of the beast (as an atheist), the more sense it makes.