I've never used her for that on DMM, but the choices are a lot more varied there, so there hasn't really been a need to try that with her.
Overall, I'd say the main advantage of her class is the extra range over a mage/bishop. She's still going to fire slow, and she doesn't have a blast radius increase skill like some of the other artillery officers. To do what you want, you're almost certainly going to need a high MR tank to soak eyeball lasers as they close in.
Since her skill changes her damage type to magic, you can think of her as more of a real mage than the other artillery units available. There are better choices among the artillery officers for what you're looking to do on DMM, but it'll probably be awhile before any of them make it over to Nutaku. Especially at the rate we're progressing lately..