Waste yarn co

I am just starting the phoenix bess Comfy Pullover Lite, and it calls for the cast on to be done with waste yarn, and then cut away and redone after the body is finished. I have never tried this before and wonder what the advantage is. I am tempted to just do it the normal way, why not ?

Sometimes the provisional cast on is used to make a hem at the bottom of the sweater. After knitting 4-6" the scrap yarn is removed and the live sts are knit along with sts on the needle. Doesn’t sound like that’s happening with this pattern. If all you do is pull out the scrap yarn and bind off and if there’s nothing special there about the cast on then go ahead and use your favorite.