Magic. Magic, and her character would be completely broken if there wasn't a significant drawback to being Hidden.
For best results as Dusk...it depends on your preferences, you hide for at least one turn to reduce incoming damage and try to either kill enemies, neuter them with Weakening, or recover health before you hide again and build up lower anxiety since there are fewer enemies to dodge.
Kunai, Scaring Shot, and Weakening Shot get really, really good once they're at max level. Include Kunai Belt if you're not going to be mixing herbs at all--now that Dusk can't cycle her deck as easily, it might be better to upgrade how many cards she can draw at the end of each area and just spam throwing knives. I'll give that a try in a minute, actually--I used to combine Scaring Shot with Strength Potions, Whips, and Double Slash. Apothecary, Alchemist, Calculated Risk, and then lots of damage until it was time to throw on Invisible Cloak or Shadowstep. Also used Pocket Watch with the ability Winds of the Vale for quick bursts of mana.
People used to be able to just stay Hidden for entire battles with Priestess's Gift or Naturalist cards. It's possible to use Weakening Shot to neuter basic enemies, but slimes and wyverns will still mess you up. Poison is Dusk's equivalent to piercing damage, so it's not useless, but it's slow--the Leftovers card turns into a reliable means of dealing massive poison/pierce damage after you grind through potion after potion. So 0-cost Forage cards would probably help with that. It might be fun/doable to build your deck around Smoke Bomb Pouches.