Like most measures that give more power to governments, it makes things easier for them, not possible. Are you honestly not aware of how unique permanent identifying numbers give governments more power over the people thus numbered? There are examples in the article.

US passports, among others, do not have a number identifying the holder, only the passport. Each time you replace the passport, every ten years or less, you get a new number. The passport also does not bear the social security number.