It's also a significant loop hole. Given the number of times that the Girls get sliced and dice in their abdomens and then regenerate, i don't see how they can regenerate the stitching too. Yet their insides don't all just fall out as the manga implies.
I'm talking about the threads that's holding the gash close. It's stated without the "surgery" the guts will just fall out. And these girls have been sliced open plenty of times. While they regenerate their bodies, I don't see how they regenerate the threads they need to hold themselves closed.
It's likely due to the fact that a Claymore's body can only heal what can be healed, and in some cases what can be restored in a given amount of time, if I'm correct. While they can certainly heal the various cuts they get in battle it often takes a well placed injury to truly do one in, specifically where the thread is at and it's likely the Claymore will die no matter how good her healing ability is.