http://cdn2.geekifix.com/wp-content/uploads/2019/01/21.jpeg If this is the isolation left to right, it seems like plenty bordering on overkill. You can't just feed wall power into the transformer in a switched power supply; the power needs to be rectified and then fed to it at tens to hundreds of kilohertz. The chip bridging the gap is designed for this task, with builtin isolation.