A ‘smart’ trainer is one the communicates via ant+ or bluetooth. They come in both wheel-on and direct drive, that has nothing to do with it. It will usually measure your power somehow, and send that to your computer/device, and then the other way a program can control the resistance. (A ‘dumb’ trainer usually has a lever where you can manually increase resistance, but not do that automatically). A power meter will also report the power you do, but off course it can’t control resistance.
If you just follow the blue line in TR, it’s fine to use a dumb trainer combined with a powermeter, and just pedal harder when the line goes up. But with a smart trainer, you can have the blue line control the resistance, so all you have to do is pedal, and it gets harder/easier on its own. For zwift, if you want to feel the hills etc, you need a trainer that can do that. All of the ones you are looking at can do that.