The issue is how it will be enacted. It will invariably require transmitting personally identifying information across a network and for it to be stored somewhere for processing. Even if this is done as safely as possible with government systems, there is always the risk of data theft and exposure as well as excluding people that don't trust the government at all, like pretty much every Indigenous person I've ever met.

It as well provides the government with a system and store of information that could be used as tool of oppression.