Advantages of scaring a guard

During loading screen there was a tip that said something about scared guards being an advantage, but I wasn't paying attention and I didn't really get to read it all. Now I've been noticing that a scared guard is more annoying then a normal guard. They move erratic, turn around right when I am about to stab them.

Am I missing something? Is there an advantage in scaring a guard?

Terrified guards tend to wander off elevated platforms, killing themselves. They'll also fire their weapons randomly, injuring or killing other guards.

They do have a tendency to turn at just the worst possible moment, so you're generally better off surprising them from above or below.

The Path of Nightmares costume will cause any guard who finds a body or witnesses a stealth kill to become terrified, meaning you can terrify guards by hucking the bodies of other guards in their general direction. This is perfect for dealing with guards who are in positions where it's tough to surprise them. It can also be useful in areas where guards are so close together (or have short patrol routes) that they are likely to notice a body before you can move it.

In fact, terrorized guards behave extremely predictably (as least, this is on the PC version). All terrorized guards behave essentially the same. They will alternate between looking left and right regularly (NOT erratically). They will slowly move along the entire platform they are on. If there's a ramp on the platform, they will walk on it when they backtrack (again, walking over all the ground available). On entering terrorized state, the guard will stumble backwards and fire shots in the direction he is facing/what scared him. Additionally, anything that would startle a normal guard (sounds, dead bodies, etc.) will cause the same reaction (stumbling and firing). This INCLUDES SEEING YOU. After a period of time, I've noticed that guards tend to stutter-step in one spot. Distracting him will "reset" him and cause him to come slowly investigate.

Terrorizing guards is crucial to getting high scores. You get +300 for terrorizing guards, and +600 for friendly kills (the max for kills, you can also get +600 from hangman's hymn, prowling spider, ninja tool kill and object kill).