1:1 voting is just one minor benefit of having a general ID instead of depending on evidence of an identity.voter ID of any kind is only of use in preventing in person voter fraud i.e. turning up and pretending to be somebody else who is entitled to vote.
All the talk of uncontrolled immigration and (at the moment here) "multiple identities to commit social security fraud" are successfully combatted by having one legal document to identify youself against any state agency.
The security risk you have to cover of course is that it doesn't make you completely transparent and is not used in big data applications to tie all your other profiles together (that's why I have not activated the "e-government" function of my Personalausweis - let's be realistic, state employed IT goons are a bit on the weak side).