For the uninitiated, the NZ VORSEC Minimum Reception Altitude (MRA) chart is similar to the 25nm MSA chart except that it normally extends to 40nm and the minimum altitudes depicted are based on navigation aid reception. It is specifically designed to assist arrival planning.
I think the crucial point is that the 25nm MSA does not guarantee navaid reception, and that is probably why many States designate it for emergency use only.