I'm pretty sure you won't find it anywhere else- at least it has not been a factor with any of my license conversions... but am prepared to be corrected.
Believe it's original intent was to allow some lee-way to PVT VFR pilots to complete a flight just after end of daylight- not, as it can be used, as a take-off into a dark night with no instrument rating and/or WX radar kind of thing.
The "intermediate step" comes about from australian flight schools using it as a precursor to an IR, as it provides some basic instrument training. There is no requirement to hold a NVFR prior to an IR.
HJ