Well it will lighten the barrel a bit, but personally I just like the way they look, and I think that is the main reason for them. It's the same as fluting, although it has some advantages in weight reduction, it also looks nice. I have a mkIII competition with the slabside and I think it's a really pretty gun. My gun store actually had the fluted hunter in stock but I had them order the competition because I liked it that much better.