1. Literally every American social program uses census numbers to allocate resources.
Your fire department, your schools—the data gathered in the decadal census, determines, for example, whether new schools are opened or current schools are shut down. Transportation grants and education grants, among others, are distributed proportionally. If the Veteran’s Administration wants to place a hospital for elderly veterans, they obviously want to select a location heavily populated by elderly veterans. If the numbers are off, the hospital gets mis-sited—and the vets don’t get health care.