Watts:
Platforms such as Zwift have an architecture that calculates Watt/Speed and according to many experts including Niels Andersen this is a major mistake.
1. If you take 2 riders IRL riding Side by side with a speed 40kmph and pushing for example 300watt.
2. One rider falls back in to the draft and to maintain the same speed he will only have to push app 200 watts due to real life draft.
3. With Watt converted to speed he would then fall back. But we know that Zwift and other platforms using a virtual draft, they give you extra speed (Sticky draft) and will allow the watts to seem reduced.
But in Zwift there is not a real drop in resistance and therefore you will continue to feel the resistance. You will discover the only thing that reduces is the watts which is what you see on the screen, nothing else.
4. Now new example IRL. Cross winds and the rider that gets the wind from the side will now have to push 400 watts to maintain the 40 kmph but the rider on the other side only need to push 250watt
But with Watts converted to speed the rider that push 400 watts now goes faster
But the problem is, that Zwift cannot give this wind or draft feeling, because of the architecture they employ within the game.
Last example:
Cobblestone effect and resistance works as follows IRL.
You inter a sector at 50 kmph in IRL and you fly over the stones, but the slower you go the more you would feel the stones = resistance. But if Zwift change the resistance you will push more Watts and go Faster.
Converting watts/speed is ok but it is an easy fix to a complex situation