I was always led to believe (and was procedure in past airlines I have worked with) that cabin lighting is dimmed to give pax and crew a better chance for their eyes to adjust if we had to evecuate at night.
My current airline insists that cabin lights be on full birght for all take offs and landings, with all window shades open for maximum visibility of the aircraft at night. Makes sense really, think about it. How often have you seen aircraft taxi, take off or land at night, in the pitch black with only their tail visible, if that, compared to an aircraft with a full row of lights either side. I have found it difficult at night to identify the airline let alone the size or type of aircraft many times, depending on the airport.