My Tacx trainer (wheel-on) has a power offset - it reads about 8-10% high on wattage. I’ve done a test vs a power meter after a calibration to check this, so I’m assuming that is all I can do. I have (at another house) an Elite Suito trainer which is spot on to the same power meter/bike.
The feature I’d request is the ability to register a specific trainer in my profile, and to enter an offset for that trainer. Currently when I switch houses and trainers, my FTP is off, so all my training zones are off, and races aren’t as fair as they should be when on my Tacx. Since one can already cheat on races easily by adjusting their “weight”, I think it’s sufficient to trust the honour system for this feature.