The problem with crit casters is that you need a skill that directs the stars to you, because unless you can consistently get 50 stars a turn, the distribution is going to be too inconsistent. You can put a seal designation on her or other crit absorb CEs but you're already trying to compensate for a deficiency she has.
And I have Helena at NP5, and I wouldn't use her if I all I have to attack with are face cards. Even with her "high" attack she still hits like a wet noodle. And Helena's support kit is... Easier? Like technically miyu's np would push herself over the edge vs Helena but for an np you're meant to be spamming it sure got tied with a really spam unfriendly demerit.
Also it's 500 heal per turn at np1 and 1000 at NP5 which is crazy low. And you can't up he np easily like Helena because she's limited.
