DS248:
Only the braked towing capacity is higher for the Kia. I doubt that many privately owned trailers are braked?
Plenty of privately owned trailers are braked. But you don't have to brake a trailer until a GVM of 2,000kg.
The manufacturer's tow rating has no statutory standing in NZ. Land Transport recommends they are adhered to.
The 750kg unbraked is based on Australian legislation, which I understand require brakes on light trailers over 750kg.
If I had an EV towing vehicle, I would be looking to do as much braking as possible with the vehicle, rather than the trailer, in order to capture that lost momentum via regenerative braking. Trailer brakes will just convert it to heat.
I'd be going for electrically actuated hydraulic brakes, with a controller. You can then control the sensitivity.