The fully-general continuations that call/cc creates require copying chunks of the stack to the heap for storage and back again when they're used. (Or pointing

The fully-general continuations that call/cc creates require copying chunks of the stack to the heap for storage and back again when they're used. (Or pointing the stack pointer at the heap, which I find even more cringe-inducing.) They're memory hogs whose lifetimes are hard to reason about and they provide relatively little benefit to most programs, which is why Common Lisp doesn't provide them.