On one hand, she's actually not bad, being a flashbang unit with a solid backup skill (If it's vs. a boss, she becomes a shielder tank instead with some minor evasion buffs) that also helps kill mooks faster. On the other hand, she has a mod3's price tag and opportunity cost, at a time when there's lots of nice mods running around.

If you already have a nice set of mod3 dolls, go ahead. If not, consider saving it for later.

...Oh, and you can save yourself the trouble of getting her mod equip. It's kinda pointless on a tank.

Her previous iteration can be found here

So if it hasn't been said enough, absolutely get the Mod1 the very second you can. It's 200 fragments and some cores for a fair boost in performance. Extra stats, a bit more FP buff on her tiles, a little extra HP, and an improvement to the slowdown effect on the smoke.

The real problem is her 2nd skill is janky and not extremely practical. It's a little bit of a bonus, but not likely to make or break a fight. So yeah, the Mod2 isn't great. The mod 3 however, gives her a unique equipment that goes in the suppressor slot and is basically a suppressor with better stats (+5 EVA over normal) which helps her tanking ability somewhat. Whether this is worth it up to you, but definitely get the Mod1 at least.

The rest of this is basically the same song and dance where she has top class offensive buffs that continue to remain unmatched among SMGs, so you WILL likely continue to use her.