Why is the fire not rendering when sphere (domain) in viewport is hidden? The actual question is basically what I'm asking.

The Sphere is the domain so the fire and other animations will be contained within it. I would like to hide this sphere for a much more realistic appearance to the scene, yet when the domain is hidden and I hit playback there is no fire animation, not even a flash. I also have the issue when switching between rendering modes.
Think of the fire as a object, and think of the domain as the renderer ~ you will not be able to see the fire without the domain. You can just bake the cache if it lags too much on raw playback.