> that there’s no way the app will have the answer ... Hey, my credit card isn’t working, and maybe it’s because of a weird charge I had on it yesterday, but then something else happened right before this purchase” – that’s the sort of complicated scenario

Hmm, what makes OP think a chatgpt can't answer this question? Given enough tokens passed to a ChatGPT session, a chatbot can eventually find out what's going on and provide a simple to understand explaination.