I guess for me (and others) this kind of tool represents another piece of precision kit that helps us maximise what we've got with minimal effort
It's a reality, we could all buy a cheaper charger and a cheap/decent multimeter (i.e. to do Watt tests etc.) and still achieve some measurements but we move into the hassle zone, where a lot of folks would rather not go but instead we pay a bit more for something that gives us additional information without effort required to calculate etc.
In addition I see it as a valuable troubleshooting tool. I've had situations where the AMP output is not what it should be given the C rating notably at the start of the current draw and over time. Where do I go next? Is it bad joints/leads/cells/speedie etc etc. Coming from an IT background I always like troubleshooting at the source - in this case the Cell.
If Paul can provide a tool (with a decent reference sheet) that gives us some clues as to the performance of the starting point of our power without having to go through calculations etc. then I see this as a good buy as I KNOW that a lot of the RC flyers out there don't feel comfortable entering the maths zone
and we know how many *what the hell* threads there are out there re doing something as simple as calculating the right prop!.
Maybe some info would include comparisons between IR of the Cell and what is being seen at the Deans plug (in the documentation?) would also be helpful.