Although the provenance of the control is to deter and detect fraud, it also helps to highlight key-person dependencies (where a process cannot run without a specific individual present). On the flip-side, humans are very innovative creatures and you can use this control to identify where someone has found a way to bypass parts of the process (the process time suddenly increases a lot when someone in the team is on their mandatory-vaykay, or the quality suddently drops).
I also see it used in smaller companies by bosses who want to simulate the effects of a person quitting, and how confident the rest of the team are to take over the running of a task.