Certainly central. That concept captures two (at least) of the effects on my old post about the meaning of free invocations...

Sure, and your post goes into the effect that that has on the game, whereas I think this gets to the heart of what aspects really "are".

Effect vs. cause, if you will.

(But, to be clear, awesome post).

Yep... and it's very good to look at things like this from all sides, to really get a handle on them.

.