I downloaded this thinking it would give me the ability to watch YouTube on my Apple Watch.
I was sorely disappointed to find out that once purchased it would not let me log in to my Google account to see my playlists or saved videos or anything. Also, searching on the watch, you have to use voice commands instead of using the draw-to-type, otherwise it crashes.
The app has not been updated for over two years so it looks like Google no longer allows access via login.
I think mostly this is a remote to control the WatchPlayer app on your phone, just like all the other apps.
The one upside to this app, even though it’s paid, is that on your phone, the app supports picture-in-picture playback, unlike the native YouTube app. The drawback, again, is that you cannot log in to your Google account to access your own YouTube channels, so you have to manually search for the video you want to watch.