That trinket is a short duration ability. Since mastery only has pvp utility for some classes, I don't see this trinket used by very many.

That said, I do intend to aim for this on my DK tho, since this is a great tank trinket, and Frost DK trinket for pvp. This would be not so stellar for a Ret pally, and kinda subpar for a shammy since on use or on proc AP or SP trinkets are what enable the short duration burst, which gets us our kills.