It just applies to Americans because their criminal records are not centralised. Meaning they can have different criminal records in different states. Some people used to get CBC's done from states that they were living in which showed that they had a clean record. When in reality they had committed offences, been caught, and had records in other states.
The fingerprint requirement is for the FBI who do a centralised CBC from all states. It's a major hassle for Americans, for sure.
I was a tad confused by your heading but as a Kiwi I would just like to say... Australian, Criminal background, Check! Just joshing :)