Wiring a switch to PC Lights

[Samw]

I wanted some cheap slim lights for my overhead refugium and the 18W Coralife Aqualight was it. So I bought one and took the internals out so that I can mount them without the canopy. I bought a new switch and wired everything back the same way as they were before.

However, I noticed that the switch in the original configuration was placed on the neutral wire coming back from the ballast instead of the hot wire going into the ballast. What are the implications of this? I thought most people put the switch on the hot wire. Here is a pic after I wired the lights back up. It works fine. I'm just wondering what the difference between putting the switch on the black wire vs on the white wire. I assume the voltage on the wires coming out of the lamp will be lower. What else? Any advantages or disadvantages?