I'm going to Colonia myself and i tryed few NS charged jumps. I also made some math.
My 2 cents are that indeed the number of jumps to cover a KLY is halved or better, if you superoptimize can be closer to 1/3 of the route plotter.
This beeing said it is true that if it is time efficient or not depends much on your flying skills, and also on the ship you are flying.
With my 54 LY Anaconda, 1000LY would take 19 jumps with the route plotter, while using a NS route it would need 6 or 7. But since the Anaconda manuevers like a falling brick, and i am on the super safe side, getting those NS charges takes a lot of time, so in this particular case i think the route plotter is faster. Also since I have to refuel every 2 jumps, I have to bookmark a lot of sequence stars in the route to refuel, or i have to make suboptimized jumps to save fuel, but after 2 or 3 NS i have to stop by a sequnce star anyway.
With this i don't want to mean that in my opinion the NS highway is not good. On the contrary I think that if you want to bring an AGILE ship to Colonia, that has low jumprange, NS highway is going to speed it up. And above all, if times are almost the same, would you prefear to do an ocean of hink-jumping, or 1/3 of an ocean of jumps, but with an interesting gameplay mechanic that keeps you entertained?
Since in Colonia there are stations, eventually many players that are not billionaire would want to fly their not explorer ships up there, and an Highway that makes you save some time, or at least amkes the trip entertaining, is surealy super good.
So thanks to Erimus and all the others that have put efforts in findings these highwways and trailblazing them.