What is the point of the "Beseech the Chaos Gods" Strategem?

[Vorenus]

Ah, ok.

[Gothical]

Ah, ok.

 

Yup. Useful little stratagem that, especially on Terminator/Jump Pack Sorcerers that might find themselves in the perfect position to use a spell you really wish you had chosen. It is very fiddly to base a strategy around (and harder to explain), but it is nice to know you can take a Mark for access to one of the survivability-boosting spells but begin the game with two potent/more immediately useful ones from the Dark Hereticus discipline (or even vice-versa - tank early on with the survival spells then switch to Warptime to close the gap with your melee unit and avoid rapid-fire range).