soon in Zürich there will be a vote to create a "City Card" or City ID that the City could issue to all the residents. As far as I understand the main aim is to help people without official documents to live their life in the city.
My question is not about the ethical or political aspect of the proposal, nor being in favor or against, but purely technical: how would such a card work? In abstract, people without a permit should not be in CH. Of course I know there are Sans-Papier due to many different reasons, but what would be their status if they get a City ID? I think other cities have done that already, how does it work there?
I have searched and read online, e.g. https://www.zuericitycard.ch/ . The site provides 5 examples of usage of the card: to call the police in case of violence, to apply for kindergarten, to receive registered mail, to receive first aid, to get married. But it's still not clear to me. Does it mean that a document issued by the City will officially replace in validity a (lacking) document issued by the Federal Government? Isn't there a legal conflict?
As I understand it, there are many people living in a country to which they have no official right. However, it is not practical to throw them all out (as you rightly say, that's a political, and therefore completely different discussion). Some of them are known to the authorities because they are trying, as best they can under the circumstances, to work out their lives as best they can, ideally also legally.
The City Card would be a limited document to prove one's identity. I think it would be valid in the City of Zurich only. Therefore, no, it is not instead of a federally issued document. And it is not for people, such as you and me, who are in the fortunate position of having a citizenship and an established life in Switzerland.
The hope is that this should also open doors such as in the 5 examples you've listed, but also cut down the costs and trouble whenever a person without a formal ID-document were be stopped by the police (which, at present, is a costly and time-consuming procedure if the person has no ID, but it doesn't actually lead anywhere. The City Card would put this bureaucracy back with the registration authorities, and no longer burden the police with this extra work.)
This City Card is an attempt to regularize a provisional and confusing situation. It is trying to provide a definition, in a grey zone. It is a way of facing reality. Yes, you are right about a possible new legal conflict, and others exist already. This is the hope of diminishing those.
For example, schooling is compulsory for all children living in Switzerland. However, unless their parents have ID-documents, and sometimes unless the children have ID-documents, trying to register them for kindergarten and school can be a nightmare. There are children in Switzerland who aren't in school at all! That isn't right. With the City ID, at least this door would be opened.