I'd say both questions depend on a number of other factors. 99 passing vs 99 D awareness, what is the positioning of the defender, how long did the passer hold down the passing button, where it the guy who's supposed to be receiving the pass, is the defender holding down vision control, etc. I think you're making it out to be too black and white.
Either way, does the exact percentage matter? Just know that turning up the d awareness will increase the chance of breaking up passes while high passing will decrease the chance of a pass being broken up.
As for intimidation and its worth, that is a very subjective question. I'd say the answer depends on your style of play, your player build, your teammates, etc. It's not really possible to answer that on a forum, I'd say just go out there and try it and see if you notice a difference.
To me, intimidation has the same type of effect as slight lag. It's not necessarily noticable, but sometimes if feels like you're fighting an uphill (or downhill) battle. Your pokes don't work, you loose the puck seemingly for no reason, players bounce off checks, you get beat picking up loose pucks all game even though you seemed to get their first, etc... its not as extreme an effect as it was in 11, but it still can have value when used in the right situations.