be interested to get your feedback - @kurt.braeckel’s experience is obviously different to mine. There are lots of posts on TR about it, both positive and negative. Much seems to depend on the trainer/powermeter combination - what gearing - what cadence - what workout etc etc.
Why not do a test recording on a garmin from your power meter and TR from the trainer in normal ERG mode - you can see how close the power is over each interval ? I did that a few times and I found that my power meter was pretty close to my trainer power most of the time, close enough to be usable and the difference wasn’t worth, what I considered to be, the reduced TR experience.
Ultimately, for training purposes, repeatably is arguably more useful than 100% accuracy. How these indoor ramp, 8minute, 20minute tests relate to what you might do outdoors is also very rider specific (IMO!) . RPE is so very different for me between indoor/outdoor. If you had to ride TT or Tri at an exact percentage of your (indoor?) FTP then you might be more inclined to use powermatch.
I also like to kid myself that my trainer reads low and I’m more powerful in the real world
as always YMMV