You can use a physical remote without looking at it and that's very hard to do with a smartphone. You also have to constantly unlock it to get back to the remote app if it shuts down. I love the Roku remote, it works so well and the physical buttons are very satisfying.

You can put it on your slidey down screen (where flashlight and sleep etc live) and then it’s swipe down, touch - no unlock necessary

Actually it goes straight back to the Apple TV remote without having to unlock. Not sure what the time limit is but it works after the device has gone to sleep and otherwise locked itself.

I use actual remote for normal use, and iphone whenever I have to edit text. Seems like the best of both worlds?

To be clear I use my TVs remote with HDMI CEC, not that insane apple remote.