It's true that the state has discretion on whether to pursue a crime, and this is apparently true for harder crimes like murder.

I guess the state prosecution just disagreed on this matter, I'm assuming that, within their specialty, they take the top N cases and dismiss the other pettier cases, and in this case this case made the cut according to the workload capacity of the fraud prosecution workforce.

In raw stolen amounts, it's not small at all, it's like 8 million dollars, which is an amount that can be argued to be worth one or two lives, it may be the cost of complex surgeries and health insurance, or the cost for good nutrition, living space, so it could be argued that this person is taking those resources away from someone else, no matter how inert or ridiculous the means by which they stole that money may be. If someone defrauds 500 million dollars by impersonating a clown, the optics of defrauding 500 million should prevail over the optics of "putting someone in jail for being a clown".