What would consistitute as proof of the concept of non-existance being ersased from the story?
Your answer: Proof that the concept of non-existance being erased.
That really is a non-answer.
Never Mind that:
Sailor Cosmos has auto shields and auto BFR (for even herself) and auto attack. The minute WF tries to nullify her power, the crystal will defend her. And the silver crystal has overided power negation before (while on Planet Nemesis). Not to mention Sailor Saturn's power nullification not just a specific attack, but the nature of all her attacks.
I would argue that the having Saturn's crystal as part of her ,will transfer this nature to all Cosmos's abilites, but I can more surely say that the Silver Moon Crystal Eternal Power, the go to attack that was immediately unlesashed when Sailor Moon went to go battle Chaos, not only ripped him to shreds and erased (while he was completely one with the galaxy cauldron) it also weakened him a drained his power.
So I find it terribly insane that WF, power nullifcation is going to do in Sailor Cosmos, when she's got history of no-going Power nullification from other enemeis. And has a way aroudn it: (ex. Sailor Cosmos power is nullfied, the crystal then takes power from whenever or wherever it exists, the past or future where it's not nullfied and uses that power instead)
And I'm going to have to call woopty, on this idea that a thought> a gesture. Specifically speaking gestures are just automatic and reactive as a thought. I mean, how many of us had to immediately think to defend our faces or dodge something that went our way.
Especially when Sailor Moon has fought against people who needed only to think to Attack (aka Planet Nemesis, a living Planet.
he too has power negation) yet Sailor Moon was able to deal with him.