Slaying the Target Outright

In Dungeons and Dragons 4th edition’s Player’s Handbook I. on page 288 states:

Under "Coup De Grace" there is the rule "Slaying the Target Outright": "If you deal damage greater than or equal to the target’s bloodied value, the target dies".

Does the above rule also applies to standard combat or only for helpless target and only in case Coup de Grace is performed? For me, it would be natural to apply it to any standard damage outside of Coup de Grace as well, since getting damage equal to my bloodied value seems like a devastating single hit, like losing a head or torso.

Are there any similar rules to standard use cases?

Thanks!