The Apple TV comes with a great remote, and an iPhone not only isn't necessary, the backup "if you lost your remote" interface on the iPhone is kind of bad.
Though if you lose your remote in the cushions or whatever note that your iPhone can be used as a "hotter hotter colder colder" method to find the remote. Was surprised to find this feature. https://support.apple.com/en-ca/108371
Though if you lose your remote in the cushions or whatever note that your iPhone can be used as a "hotter hotter colder colder" method to find the remote. Was surprised to find this feature. https://support.apple.com/en-ca/108371