Don't know if it's the most effective thing, but I used her because she's one of my favourite girls + provides crit buffs and 1.36x Skill Act for Hyacinth.
Okay. That's a good argument. It's always a plus when you can use one of your favorite girl.

That'd be a good idea, though I'd avoid posting my own because they're not exactly the best teams. Rather, they are typically teams that I try to include my favourite girls in.
I don't think it's really important. It's not to post the best of the bests teams. just teams that works or with nice ideas. Even if you use a girl because you like her and not because she is good, it gives a base for someone else to improve that team. Builing the exact same team is not really interesting or even possible most of the time.