The most interesting bit about the Honolulu train was it's proposed automation: no driver, just a program. With elevated guide-way, there is nothing to crash into on the track, so all the driver does is stop and start the train--the rail guides it. No reason not to automate that. But it's what automation makes possible that is interesting: increasing frequency is no longer dependent on labor costs, but merely a matter of capital development. Running more trains per hour simply requires buying more trains. Theoretically, this could make very high frequency trains (ever 2-3 minutes) technically possible. And thus enable a transit-oriented lifestyle difficult (if not impossible) to duplicate elsewhere.
It would cost money. But it could radically reshape urbanism in Honolulu. Moreso than the area around the line itself, because a high-frequency transit spine enables the emergency of a transfer network, making is possible to get between places that aren't on the rail line, but are connected to it by bus/shuttle routes.