Scar dead completely reopens all past physical, emotional, and mental trauma, (at 120% the original pain thanks to the end) so Sailor Moon would have to deal with all of that at once, also even if regen or mental strength closes it back up scardead reopens it, since it's a passive ability.
Being unaffected by space-time destruction is pretty standard for tier 2s and is very different from resisting existence erasure. But since she's listed as having mid-godly regen on her page, she must have come back from some sort of existence erasure at some point. But if she hasn't resisted concept erasure/manipulation, then Medaka could All Fiction various concepts that Sailor Moon relies on. In any case I'll bring up some of her other uses for all fiction, Medaka can erase the time her attacks and actions take, the attacks and powers of an opponent, the damage she's taken and her own death, the memories and growth of her opponent, her opponents power and durability, her opponents senses, the weapons of her opponents, probably more that I can't think of right now.
She also has lots of other skills and abilities, for example she knows and can identify all of the "weak points" of humanoids; has an ability that reduces one's power and speed to that of the "weakest human" (which apparently means city block level and hypersonic in Medaka Box) and seals all their abilities (this even works on beings who are supposedly multiple dimensions above her); an ability which pushes away all harm, physical, emotional, or mental, onto her opponent or the nearby environment; an ability that allows her to strike first (this is usually a meaningless NLF, but would be helpful in speed equalized, since it's not actually speed, but more like an rpg boss's ability to go first); she's skilled with various drugs and on the fly body modification; can electrically rewire the brain, changing thoughts, memories, and willpower and can read minds through the electrical signals in the brain; can freely change the powers and abilities of her and her opponents; she can copy the abilities and techniques of her opponent at 120%, although she supposedly can't use them if it's beyond her physical capabilities, she has in the past copied physical strength, speed, reactions, physiology, and regen, as well as abilities that aren't physical; she possesses superhuman luck, and an ability that can negate all luck and probability altering; she can create clones and make it nigh-impossible to notice her; she can make her opponent lose their sense of accomplishment and make a fight suddenly become more difficult for them; she can block intuition and precognition, as well as make her actions unpredictable; she has the aforementioned scardead ability; and much more that I couldn't think of off the top of my head.