Blessing of Freedom. When and where to use?

Is this mainly for PvP? Do you use it in tanking at any time? I bet there is alot of use for it, it's just that I havent found it yet.

I have sofar only used it Shattered Halls, to pull the whole corridor there, after the first boss. Stops them from slowing me down.

In wich instances and pulls do you as a tank use this blessing? Or do you use it at all?

Sorry if this have been asked before, I did a search but didnt find anything useful.