$799 is just plain stupid marketing by the kiwis (bestjet is former strategic/Air Australia's CEO's wife we believe)
If people will pay $799, they'll pay $999 including some ground content, either car &/or accom.
Or even $1499 with $700 ground content.
All these low fares create a benchmark in the average punters mind & they'll hold off booking in future, until similar type of fare appears.