It change almost nothing.
This law was to find your family members after long lost of contacts (years). It was to help family member reconnect after end of WW1 WW2 and after the end of colonisation in Asia and Africa. The administration do the research find the person, the ask him/her if he want to reconnect with you and if he/she wants give you the address. It's stopped because fewer and fewer people use it in the last decade.
If someone is missing, police still do the research.
If Someone need to be found to pay kids pension, to helps his/her parents, for fraud or taxes evasion, or even for some kind of family Inheritance there are others laws.