I think the Catman is saying what's the point of just using it every x weeks for testing and then not use it for training to confirm you are hitting target %s of power output. If you are using power to test you should use it to train as well, for validity and reliability. I agree with him.
You want to ride a pursuit. You're not allowed to use a power meter (track, stoneage, remember?). You want to set up and tune your schedule to optimise your performance.
With a power meter, you can test your power output with a number of different schedules and see if you're going out hard or not hard enough, and you can tune your schedule accordingly and pace yourself to take advantage of your strengths.
You're a wage slave with 2 kids and limited time and budget, certainly buying your own power meter is grounds for divorce. You want to improve your sprint. You have no idea if your peak power is high or low or what shape your power curve is. You test it, then spend 4 weeks working on the parts you want to improve maybe some weights, maybe some max efforts over different durations, maybe some high cadence work, or low cadence big gear stuff or motorpacing, and come back and test again. Has the training worked or not? Do you know? Not unless you test it. How do you reliably test it? Flying 200 at the local outdoor velodrome? What's the wind doing?
Consider this :
Same situation as case 2 above except you want to boost your power threshold for long road races. We test you, you have 20 minute threshold at 260 watts, we suggest a block of 4 weeks working on over and unders, after 4 weeks, it's dropped to 250 watts. That's not good ... but it won't show up clearly in an outdoor road ride, we need to do something else as the over & unders aren't working. We've found out in 4 weeks and we know for sure, rather than guessing and relying on inaccurate tests.
I'd rather turn on the light as much as I can for the riders I work with and their personal circumstances, than work in the dark and guess. You're advocating refusing to use the tool at all because you can't use it all the time?