They satisfy governments ever-hungry for more data on their citizens' movements, even if said data is wrong.

They enrich government contractors and their pet politicians.

This is a key reason I don't like this kind of technology. There's way too much ignorant misplaced faith in 'databases' and zero common sense, no matter how obvious or egregiious the error.

Mistakes happen and when it's obvious there's an error, the government should make it a top priority to immediately hand-walk a solution through the system.