*Hmm, I still did'nt expect the light, itself, to be visible
*The "light" is not visible. I don't understand what you're talking about. There is a candle prop floating in the air. That is not the light. There is a cone prop on the floor. That is not the light.

If you place a sphere exactly where the light is and turn off shadows for that sphere, then the sphere will look like it is the light. That's what I did in those black-and-white renders of the striped room.