I agree completely with this. If they numbers are fun for you, then that’s fine but getting fast is not about the numbers. Put fun as the first priority. Remember to get good recovery which is Zone 1 power Z2 HR a lot of the time.
In our Jack plans it’s all about logical progressions but those start out easy and should get reasonably hard when you get up to the #15-#20 in the sequences.
You could train by RPE, HR and/or feel and likely get as fast as you do training by power (I should not say that since we are a power based platfom :))
A lot of us like the numbers to see progress. A power meter gives a fairly clear sign of progress, and gives some reaonsable estimates on good targets that react faster than HR, so better for shorter efforts. Just like Dr Seiler says, don’t chase the numbers.
It’s very easy for the numbers to get in the way of our training. For me personally if my power meter pedals are dead, I am thinking, do I really want to train/go on a ride (terrible)… Have fun. If the numbers are fun, that’s fine too