It is complex question kind of 30000ft question.
I would start with counter question to stimulate discussion: what it takes to win the race? What kind of race is it, road, MTB, TT? Also what does it mean "the best time"
I’m 100% positive if used properly, Moxy will allow you to get 100% from your body, without running risk of overloading/underperforming, you will get “the best” performance out of your “engine” on a given day.
Will that allows you to get “best” possible time? I’m not sure, since there are other factors as well to get better time: bike, wheels, clothing, helmet, nutrition, hydration, stress, weather.
For given day considering the rest is constant (but it is not) using Moxy properly you have much better chance on getting perfect (not the best overal) time, than randomly looking at pretty much random power zone system. That means you could be recovered better in 2 weeks and you could get even better time using Moxy.
Since you use Moxy you will understand next section easier:
Let’s take simple power zoning under consideration. Z2 starts at 56% of FTP, in Moxy world it would be ARI zone.
From power perspective you ride this zone for 3 hours, and you have impression you stayed in the same zone. Now look at Moxy output I bet the SMo2 and ThB line will not be as flat as power line, indicating your body response to constant stimulus changed over time, as expected, but totally not taken under consideration by power meter.
Few days later you had few hours of sleep less, got some junk food, jumped on the bike going in Z2 and it feels “hard”. From “power” perspective you have no option but to suck it up and go, but your body tells you: dude I’m a bit weaker today, because you didn’t get enough sleep and fuel me with crappy food…With Moxy you will spot the difference and will be adjust accordingly.
Analogy from race car world:
Imagine Formula 1 team: tweaking the car engine, aerodynamics, fuel mixture, tire choice etc,. Purely based on best lap time…. Small gust of head wind will slow the car down and all the fuel adjustments might look wrong since time was longer when car made second pass and had wind from the back. Instead they take a computer connect it to engine and look at the mixture and exhaust in the garage, same as you would take Moxy and look at oxygen and CO2 in your basement.
Moxy is an eye in to how training and external factors affect your biological engine, power meter is just another speedometer, did you realize that all car racers only see RPMs to avoid overturning the engine, they do not care about speedometer and time. RPM meter is serving the same purpose as Moxy.
Another question I’m still asking myself: When thinking about racing and training, should we think about creating best balanced “biological engine” for the event, or about the best time? More and more I start to think about it the better engine I own, my time will improve automatically, or at list my fitness will not be my limiter in race results.
Moxy at this moment is holy grail of checking how your body reacts to the training.