I know a lot of people peg their pullet weights and I just do too, but Why do people do this?

Where I fish most, there are a lot of brushy limbs over the water. Pegging keeps the sinker from going on one side of a limb and the bait hanging on the other. I usually set the sinker a couple of inches above the hook.
I use the rubber pegs.

Too keep their weight locked to their soft plastic. Most common in flipping, pitching and grass punching. I use the rubber bobber stops, too.

Rubber bands for pegging. Grass fishing and heavy cover.

I peg it with wooden toothpicks. Cheap. Mainly use it around cat tails.

6th sense makes the best weight pegs

Bobber stopper from bass pro work good. Dont wanna use tooth picks frays line and probably hard to get out of tungsten. Plus i like when i pull up on it I dont feel the weight hit the bait and think its a bite

academy has some 100 for about $5.00.

I have used 6th sense and the ones from academy. I have seen no diff in the function. I will use the academy ones from now on

It will eliminate some of those hook sets from a moving weight.

The rubber nails are hard to beat. I think they hold heavy weights better than bobber stoppers, especially heavier weights.

I have both but the 100 pack of rubber nails are cheap and hold the best IMO.

Well, WCBLASS on here showed me how to do just that using toothpicks for a Texas rig and curly tail plastic worm.
Sure seems to work. Cheap Alabama rig... I guess.....he catches fish!
Wish I did...

+1 for not liking toothpicks!

I learned to use rubber tails of jigs, spinnerbaits, or buzzbaits and to pull it through the weight

Yes, I used to use little strips of live rubber, had a piano wire puller that I inserted through the sinker and pulled the rubber back through. It worked good.

Instead of using a regular TR worm weight, rig it weightless, then crimp one or two (depends on size and weight desired)CLAM WEIGHTS right above your worm, or higher if your want it Carolina Style. The weights don't move, give you what you want to go thru weedbeds or what ever. Better than pegging. I use this when I am fishing wacky style Senkos with weedless hooks.