To reiterate. Well placed weight does help, but you may not need it where you live.
Canuck here, 4x4, good tires, and I live in a place that gets an obscene amount of snow.
A little weight behind the wheel wells, near the tailgate and even on both sides helps a ton. It gives you more traction for initial moving (in 4x4 or rear wheel). On the road it helps keep your back wheels planted on the ground to reduce slippage and side to side. If you do get into a spin the weight reduces your slip and helps right yourself back straight again.
Like it or not, weight helps. I keep a snow kit in the back that fills a deep box (tools, knife, first aid, flashlights, blanket, lighter, matches, pipes, shovel, tow straps, tie downs, pull out road sign). It weighs aprox 75 pounds. That goes on one side near the tailgate and bags of sand (aprox same weight) on the other side.
Winter ready and best chance at snow and ice driving. I need this for trips and ice fishing. Where you live you may not. Where I live we all have a kit and keep weight near the tailgate by the wheels, it is habit for most trucks and cars.