I use split shot almost exclusively. Only time I will switch to pencil lead is when I am targeting chum and float fishing with jigs and bigger floats, or if I'm bouncing or drifting pencil lead or slinky's with roe/prawns through deep holes for summer run reds.
Good points have been made, but I like the versatility (clumping them together when the water is faster or spacing them out in slow or clear water as mentioned, or even if I want to swing or retrieve a blade). I have confidence in their small presentation, especially in spooky conditions with fussy fish. Split shot for me are a stealthier presentation then a hunk of pencil lead, I really doubt it makes a difference but it is just something I am confident in (guys have been using pencil lead for many years). But my style of fishing is just using whatever catches me fish and gives me confidence to fish with, it's no fun fishing with something you're not confident in. And as for crimping, if you're using any decent mainline, you shouldn't have a problem with any damage. And also about placing beads between lead and swivel, most of the time the bead will break fairly quickly from what I have noticed. I find split shot to not makes as much of a noise/splash when casting if they are spread out and you're sight fishing for summers or something like that. Plus adding and taking off weight with ease is a nice bonus too.
I remember fishing some really skinny water last March and hooking 6 steelhead running two small split shot and a small float with my buddy not touching a fish with pencil lead. I just believe it presents your bait a little nicer to the fish in some conditions.
But as I said earlier, fish with what gives you confidence. Its all about how you present your offering to the fish, after all, the fish is biting your hook and not your weight. Pencil lead and egg weights have been used for decades and certainly works, its just personal preference most of the time. Every type of weight works, but different types of weights can certainly be utilized under different conditions to suit the type of presentation you want to offer to a fish.