For me, a LR tank has real benefits even outside of remote areas.
For example a recent trip to Cape Otways used a bit over half a tank from Melbourne. Now the Cape isn't isolated like say areas in the NT, but when we got to our campsite, late afternoon, I didn't feel like going for a drive to find a servo, and there would be no guarantee the thing would be open. So that meant the following morning we had to be careful about where we went and what fuel we used and plan the trip to include a servo.
With a LR tank you fill at the start of the weekend and no further worries. I could give many more examples like extended High Country runs. Camp at Talbotville and a fuel trip to Dargo is the best part of two hours, which I'd rather be using for other purposes.
It's not absolutely required, but for me it's well worth it. As for cost, yes you won't recoup it, but it's more than skipping servos, I could easily have made a 60km round trip just for fuel that I simply wouldn't have needed to make with a LR tank.

