Does a streaming stick work on a Roku Smart TV? In other words, does the stick "override" the internal mechanisms in the smart TV? Or is the stick useless on the Roku Smart TV?
You can use any Roku device on a RokuTV. It's just another connected device like a cable box or Blu-ray player that connects via HDMI. Using your TV remote you'd select the input the stick is connected to and then switch to using the stick's remote. You can have the TV always power on to the sticks input, but if you wanted to switch its input to something else (e.g., Blu-ray player), you'd have to press Home on your TV's remote and then select the other input.
You can use any Roku device on a RokuTV. It's just another connected device like a cable box or Blu-ray player that connects via HDMI. Using your TV remote you'd select the input the stick is connected to and then switch to using the stick's remote. You can have the TV always power on to the sticks input, but if you wanted to switch its input to something else (e.g., Blu-ray player), you'd have to press Home on your TV's remote and then select the other input.