I don’t have a power meter, so it’s irrelevant how accurate my trainer may or may not be to a power meter, although incidentally DC Rainmaker found the Snap to be very close to his power meters.
Without a power meter, as long as the trainer/tyre pressure (etc) settings for each workout are consistent then all is good.
The point I was making is that the claim that smart trainers in ERG mode are incapable of changing resistance in very short timescales (eg for sprint bursts) seems to be a myth, at least on my sample of n=1.