As many have said, clips provide easy access and protetct the knife from random stuff in the pocket. Keeping the knife away from random stuff in my pocket was the reason I started using a clip. Actually, to protect other stuff from the knife (Leatherman Wave) I always felt like it was crushing some this or that, or in my way when I wanted stuff from my pockets. But now that I use them, I love the easy access of them. Whenever I carry a folder without a clip, it is in a sheath/some sort of belt pouch so I can easially get at them, but a sheath is not always something I want to/can have on me. So the pocket clip is the easy alternative. Personally I preffer sheaths, but they can be bulky or frowned upon. I do, however, understand why people dislike clips. Speaking from a Balisong point of view, they destroy the aethestics of the knife, and they just feel odd in your hands, why ever would you want it. But for EDC, clips are usually a must have.