You pose a valid point, but on the other hand, if the Trident comes 'not broken', then why re-calibrate it. I've spot checked it through my month of it being in use, and it has tied out to Salifert within a very reasonable margin of error (there's always a margin of error, whether salifert or Trident itself; hobbyist testing titration methodologies aren't that precise). I have the calibration solution, so maybe I'll just do it tonight.
Honestly, I don't care about whether my alkalinity is 8.5 or 8.0. I want to see if it is trending, how it is trending, and the relative levels over time. It's a headache and I don't have the time to test once per day, which I have been doing for a number of months trying to diagnose my calcium reactor issues and ultimately dialing it in with a new tank. Now, I see the altitude, I feel confident since it has tied "close enough" with my salifert test kit, and when the slope starts downward, I dial up the calcium reactor needle valve slightly, and can watch to make sure it isn't going too high or too low based on that.
I have an hour and a half of free time per night, just enough time to spend some time with my family and spend a few minutes looking at the tank. I'd rather not spend 20 minutes futzing with the potential of an hour or two of diagnosing if the numbers are off. Trident frees me up from having to do much more than spot check it now and then. I don't need clinical precision, mostly just trends and rough altitude of alkalinity. Same requirements of my corals.