its a bit tricky to use.
You either have to use it immediately so no other notification can slip in between, or you use it multiple times to cycle through the last few notifications until you find the one thats actually interesting for you.
But i agree, a hotkey that only cycles through attack notifications would be much more useful.
This might be a case of auto everything though, as it takes away a bit of the knowing where your units are and looking at the minimap to see if something blinks at the wrong places.