You don't. And it is valid for most "e-sports".
But I don't understand Zwift anyway. A big part of the joy of cycling is about being outside, feeling the wind, handling your bike. The actual physical exercise is important but it is not the whole thing. I understand pro racers using turbo trainers when the weather is so crappy so that they can do specific structured training necessary for their job. But amateurs??? If the weather is too crappy (which only really happen in freezing temps or storms), just do another sport or focus on another hobby while waiting for the weather to be better.
Note: I am saying that as a former elite racer.