A few weeks ago I had a situation where I had Zwift set to get it’s power readings from my Kickr, but (somehow) it selected my wife’s Kickr as the controllable trainer.
As a result, during my ride Zwift was getting power readings … but it wasn’t controlling my Kickr.
Obviously, if the power source does not identify as a controllable trainer, you want the trainer to be selected.
Perhaps pop up a warning if the power source & trainer are different (when the power source is a trainer).