The Qantas fuel policy is not an exemption: it is a fuel policy approved by CASA.
Which it would appear at face value exempts you from the limitations of a CAT I approach, if you get caught out, which would make it an exemption to the rules.
Some airlines that have an alternate everywhere, get around it by using airports that are very close to their destination
And the point is?
Alternates have nothing to do with distance and everything to do with weather.
No problem having an alternate 40NM away. In some instances where they are separated by mountains the weather patterns are completely different.