Because Vikki will become addicted, being a moth after all and her species loves sugar, especially tree sap. (Don't be surprised if she has a stash of maple syrup somewhere in her lab.)
She manages to control the sugar, by eating the right amount, but sometimes, she will come across something very sweet and this will greatly stimulate her brain to have many ideas for inventions, even if some have no sense.
But above all, she will not want to stop consuming a lot of sugar, as long as it stimulates her enormously, without worrying about the possible consequences.
