Throughout history, tyrannical rulers have created their own private operations outside normal chains of command, run by people like Prigozhin, who are personally loyal. This give tyrants flexibility to do what they want without bureaucratic opposition. It protects them against revolt by their subordinates in the chain of command. And it gives them deniability when operations go badly.

Source: Putin, Trump, and the Privatization of Tyranny | The Smirking Chimp