Questions about passive uncrushability

I'm by no mean close to getting passive uncrushability any soon. However, after reading something about this, several questions come up to my mind.

1) Where in the game does passive uncrushability make a different for tankadins? For warriors, passive uncrushability probably help them survive fast-attacking boss better as they only have 2 charges of Shield Block. I don't know if any boss in the game can eat up all 8 charges of Holy Shield, and trash mobs can't crush during AOE tanking.

2) One statement I read stated that passive uncrushability hurts tankadins' threat, because Holy shield is a good source of threat. I think this statement is probably wrong, as I don't see why we can't have Holy shield up after we have passive uncrushability. Can anyone confirm?

Thanks in advance!
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GO GRIND YOUR S1 GAVEL YOU LAZY $#@!%$ DAMMIT!

Passive uncrushability is really just a toy for Tankadins, useful for pulling off "stupid paladin tricks" like solo'ing Garr and other old raid bosses.
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You can still have it, your blocking won't change at all, just that. BLocked hits under HS will still return damage.
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Quidquid latine dictum sit altum videtur (Anything said in Latin sounds deep)

I'm getting close to this (though the Tuskguard change set me back). I think it would be interesting to tank heroics in a passive uncrushability set. I think it would interesting to see if Tidewalker murlocs and Hyjal trash could be done as well.
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