there's other factors too.

for example one of the expensive LB executions has a long animation time but the health/enemy-break comes earlier in the animation.
(the one where he impales the body high up on his lance before kicking the lance out of the way.)

SypherPK was explaining this on his stream the other day. (then proceeded with a few examples where any other executions would have got him killed but this one saved his ***.)

P2W confirmed, incentive to get expensive execution for an edge in-game (calm down just kidding)