Switches activate relays. Relays can isolate the power if you will from th switch. You don't want the power for four offroad lights going thru the switch.
When the switch activates the relay, if you wire it correctly, power will be drawn from the battery without touching the switch wiring.
It really is a safety thing.
And you can find good switched power lines by your glove box and fuse box to power the switch.
If you need good switches consider the Carling Contura switches from www.otrattw.com
If you search my profile and look for threads I started I have a writeup for wiring lights that may help.