I'm sure there are plenty of reasons it can be advantageous to be able to attribute covert action to some independent group, but at least one comes from fairly

I'm sure there are plenty of reasons it can be advantageous to be able to attribute covert action to some independent group, but at least one comes from fairly recent US history: the Iran-Contra Affair. Different parts of a government don't always agree with each other, and one might want to be able to act without approval from another. Not all countries are one-party dictatorships where warfighting departments can just do whatever they want.