The Peloton Power Zone workouts are effective because they are basically sweet spot interval workouts. You can find similar workouts on Zwift, TrainerRoad, and several other platforms. If the training has been working for you (sounds like it has), I don’t think you’ll find those other platforms noticeably more effective, so it comes down to the experience more so than the results. If you enjoy Peloton and the spin class vibe, probably no reason to change.
The real magic of Zwift on a smart trainer is the other stuff you can do like group rides, racing, meet-ups, etc. The smart trainer’s ability to control resistance in response to the virtual terrain adds an element of cycling realism that doesn’t exist on Peloton. I personally like Zwift better because it’s focused on cycling rather than spinning, and I love Zwift racing, but we have a Peloton too and I enjoy throwing in a Power Zone workout once in a while for a change of pace.