The first 6 star SMG, and oh boy, she deserves it. As long as the damage isn't so overwhelming that it can kill her dummies outright, she has a chance to negate the damage. The chances increase if the enemy has more debuffs or has Marks of Vengeance on them, which immediately makes her a good pair with M4. Also the Sop doll is cute and comes with weird features. This is literally Sop's fault.

Welrodski! ...By which I mean she's basically Welrod but 3 star, with lower numbers and an aura that wants her in the middle (or front works too). Usable if you lack Welrod and honestly not actually bad, but HG builds are cheap and she's pretty common so she might get annoying to get eventually. Also her -acc skill stacks with Welrod, and can be combined with a +evade skill for silliness.

Her mod has other uses and is quite interesting, see her mod entry here

MANNERS MAKETH MAN. Very good aura for DPS, and very widely used. As a bonus, she has a very good skill for tanking, and can actually be used as a tank for bamboo spear formations or helping other tanks. She has 40% base crit unlike other handguns (a trait shared with other single-shot pistols like Contender and Thunder .50.) so a suppressor is actually pretty beneficial on her, not that you have other much choice in the matter. But yes, you will be finding use for her. Note that her -acc skill does stack MULTIPLICATIVELY with other acc debuffers.

Her mod keeps her relevant well into higher difficulty content. See info on that here