Good Suggestion. Nightmaher works too. I also thought about it but there are three reasons i prefer Anemone.
1. I want at least one girl in each Squad with SingleTargetDamage or Multiple Random Hits like Anemone. Just to deal a little bit more Damage to a boss in Player Phase.
2. She buffs the Damage output of all Counterattacks considerably.
3. I like her more in terms of waifuism and looks compared to Nightmaher. Also Anemone's Skill Animation is dope
But yeah Nightmaher definetely would work as well. It's the more defensive option.
Anemone is more offensive and just personal preference for me i guess.
Maybe you can snag Easter Cactus through her future Blooming Gacha. That shouldn't be to far away in the future.