Iirc the blessing used to be like Brutal Momentum, except it was triggered by critical hits, not by weakspot kills.
So it granted a timed buff (higher tier → longer duration) that made your attacks ignore hitmass.
This was changed and now all the tiers of the blessing seem to have an identical effect.
No idea why they did that, considering that this is now probably the only blessing in the game, that behaves completely identical on all tiers.