It’d be great for you to analyze spending patterns and then pressure test that the user does have cards that are an optimized line up to cover all angles. For instance you could find potential blind spots in one’s card strategy and suggest one or more cards to address these.
To give you an example if someone has a lot of streaming subscriptions but the most they get on these is 1.5x then you could suggest a no-fee card that has a 5-10% return on these. And even suggest that cards like Amex platinum give you entertainment credits.
Similarly if someone spends a lot on eBay, mercari, clothing brands online but only gets an avg 1% on online shopping you could suggest options. Some cards will be exceptionally good for some subset of vendors and some others could up the average to at least 2%