So you can tie certain people up and burn them alive ? So you know how many to add to your kill count when you board the whole thing up and burn it down ? So you know how many bags of chips to buy ? The "why" in my first response was the important bit. You're attempting to oversimplify this.
Do you want to know "who" is in your home or do you want to know what labels you can put on people and what categories you can put them into? Do you want to know "who" is in your home or do you want to know who is labelled the way you are: a singer, a heart patient, a white guy, a hubskier? What do you mean by "precisely"? The only way you can know precisely who is in your house is to sit down and chat with them. I'm not sure any label could tell you that. What do you think?
I'm wondering why the information was taken in the first place if it's so unimportant now that it can be destroyed without anyone caring. I'm also wondering if this could be a double-edged sword. If any agencies wanted to help immigrants, they can no longer identify them without more obstacles.