The OP clearly stated he was in New Zealand, regardless of the logic whatever is permitted anywhere else is basically irrelevant.
Looks like you’ve answered your question with your latest post. Your regulations give you the choice of the two options. Be interested in your final decision. Good luck in your touring anyway.I have found the NZ standard.For trailers 2000 kg or less " Safety chain required unless fitted with a breakaway cable.Safety chain must be of sufficient strength to hold the trailer secure under all conditions of road use " Maybe it's just my own paranoia having used trailers continuously but only recently owning a UK caravan with the breakaway system. I still feel more confident with that chain though.