It's handy to have the claws if say...you're wielding a greatsword and suddenly become grappled, so you have a weapon to maul with. Some claws, the kind that actually are on the fingertips, you couldn't use while holding a weapon. But there's a bunch of "wolverine" (the X-Man) style claws that could be used in such a situation.
Claws are also one of the few natural weapons that comes in pairs usually. Which is nice because you only need a single Improved Natural Attack feat to enhance both, and if claw is primary, you get two attacks at full bonus instead of just one, among other benefits. If you plan to mix held weapons and natural weapons, claws obviously become a lot less useful.