Keyboard & Trackpad
When you sit on the couch or lying in your bed handling regular keyboard & trackpad is not very convenient right? So just use your iPhone or iPad to replace them.
iTunes Remote app by Apple is useless if iTunes isn't running on your Mac - launch it from your iPhone/iPad. Using Kodi or Plex - you can launch those too. Control apps installed on your Mac: launch, quit (immediately or with delay).
Have full control of your system: Restart, Sleep, Logout, Lock and much more. No need to stand up to turn off your display, just use your device and stay in bed.