Jack could have said all along "I was skint once, and now that I'm not I want to try and help people to live well-ish on a budget." She didn't even have to focus on cooking - it's painfully obvious that it's not her forté. Or she could collate and trial recipes from other cooks, compare supermarket deals, share info about schemes and organisations.....all things I've seen wise Frauen suggest.
But no. She had to be Billy Big Bollocks and a literal expert on everything. She's cultivated this righteous character while upholding the preposterous lie that she feeds her self, her son and some OH on £20 a week. She's an absolute dick.