When it buys things to be added into the narrative state, it certainly the hell is! and that's a strong part of the use in both Cortex Plus/Prime and in Fate. If you are not using PP/FP to add things in, you're not playing the game as designed. They both can, every bit as much as Destiny spends in FFG SW or Genesys, or 2d20 Momentum, simply pop things into existence that are then presumed to have been there all along.
"I need a thermal detonator..." plot point, crosses off the relevant stashed one at the base, "I stopped by the armory on the way out and grabbed one." - that's a perfectly valid mechanical action which has "story revision wave" written all over it.
In Dune - player spent momentum to have grabbed his father's shield belt... 3 scenes after daddy died.
In 2d20 trek... "I just happen to have been studying up on Bortalian Biology, which is similar to the local" (Temporary trait. Provides a +1 to analyze it, and probably enables getting to make more sweeping assertions.
In all three, the mechanics are directly impacting the narrative by adding things that simply weren't in the story to that point.