No not really. Categories are done on points for how you place in previous races. If you win then no matter what you weigh or how much power you put out you move up a category.
Any rider with enough power to ride you off their wheel would be promoted until they couldn't do that any more.
They don't get a special exemption to ride in races with weaker riders simply because they're heavy like on Zwift.
It would the same issue in reverse if they simply grouped riders by absolute wattage without using weight as a component. The light riders would always win in the hilly races and hold their own on the flats. Also weird.
What Zwift needs is an Elo system based on results. Just like in real life.
The pro peloton doesn't use an ELO system. There is a points system based on races placement, but outside of the team promotion/demotion every three years it's basically useless, especially for the individual riders.
Light riders are at an advantage on climbs IRL because "a light rider doesn't need to generate as much power as his heavier competitor because he has less weight to propel up hills." [1]
That's why I said "almost always". It's not like any branch of bicycle racing has weight classes. You always compete with people in your category no matter how much power they generate or how much they weigh.
