A Certificate for Public Use is used to certify that premises or parts of premises affected by building work are safe to be occupied by members of the public prior to building work being signed off as being complete (ie until a Code Compliance Certificate is issued).
It is an offence to allow members of the public to occupy or use a building (or part of a building) that is affected by building work without either Compliance Certificate (CCC) or Certificate of Public Use (CPU).
Certificates for Public Use are not required for private homes or other buildings the public does not have access to.