But, that’s IRL, here in Zwift, all things are relative to weight, physics simulation are NOT realistic.
HERE IN ZWIFT THINGS ARE LIKE THIS:
I said physics are not realistic, for example we see that considering 2 different riders in Zwift:
60kg @ 236w = 38.5km/h
80kg @ 327w = 41km/h
Or a rider who is 60kg @250W, can be as fast as a 80kg @300W rider.
In real life on the flat at same conditions you think this could be possible?
If you know something about cycling as I think when reading you, please support my request here:
Pleople is treating me there as I was crazy or something… 
So, what you say has TOTAL sense if Zwift were like IRL, but it is NOT, here w/kg are “all”.
IRL absolute power is important.