Devils & demons when tripped take 1 or 2 seconds to actually be tripped.
Part of a trip/stun build is to be able to knock down opponents and or stun them, move on to back markers in mob and after dispersing them go back and finish off helpless monsters.
It's not limited to devils & demons. earth ellies, mostly anything larger than humanoid.

This is not a game changer by any means. but it is a detraction to the overall performance of these types of builds.

So please look into that animation and speed it up a tick.