[dheera]

My guess is they probably have mountains of data that they use to optimize the probability of overspending across a population.

You may be unlikely to overspend after 20 years because you are financially literate, but if you're paying off your credit card every month, you and I are very much outliers on the bell curve of net worth in the US. If you have an engineer job you almost certainly are an outlier. We aren't the target audience of these ads. There are a lot of people in the middle of the curve who mostly pay off their credit card every month but might slip once or twice, and they want to optimize that probability of slipping.