Same reason they released the US style plates. Anyone with an old school muscle car will understand the difficulty of fitting NSW plates as the gap is smaller than standard plates. Normally you have to bend the end of the plates to make it fit.
I did find a work around for my mustang. If you get the traditional black plates in NSW, this plate is the only one which its size is reduced to fit the content. By getting a 5 letter plate rather than a 6 letter plate it fit in the room available.