No, a phone is not necessary with this remote. After setting up the Logitech Harmony software on my laptop I found the mobile version of the app settings limited compared to the more comprehensive options of the desktop/Windows version. I NEVER use my phone to modify changes, electing instead to use a laptop. When I'm not using voice commands (via Alexa or Google) to control my A/V system I use the universal remote or a tablet. I'm still tweaking my Hub unit, so I haven't yet mastered the full functionality of the remote. I've encountered discrete control limitations that were not an issue with my 10-device, X10 universal remote. Hopefully, that is just part of the learning curve and not an actual inability.