[Chaos]

A large amount of Silence Inflictions are, as Sarin noted, infliction-based. Priests in particular have a field day against silence shenanigans, between their prime stat giving Status Resistance and a base skill that cures and gives immunity to silence. If you choose to run Invocations that HSDW can't cover/isn't around for and dump status resistance, it's on you for being unprepared for inflictions.

As long as Words of Power completely blocks out the effect of damage vs. Invocations, I see no reason to give mages any chance of shrugging off silence inflictions that they didn't build against.