The app is pretty simple, really. It tries to mimic the physical Apple TV remote on-screen, and does a fairly good job.
Where it shines is text input. If you’d rather type in a search query than speak into a remote and have Siri do the heavy lifting, this app is perfect
Similarly, it saves you the trouble of entering passwords for apps like Netflix — especially when you’ve got complex passwords suggested by Safari or created in 1Password.
If you’d still rather use Siri, that’s available in the app as well. Your phone can also serve as a game remote since it has all the same sensors as the Apple TV remote hardware.