the fact you have to do 1 purchase per month is already juggling. you need to remember which 1 you have spent and which 1 you havent. i meant there are other issues like do you carry 1 or 2 or 3 or 10 cards with you? what if you only carry 2 and you have a 3rd transactions, and if you carried 2, you have to remember which 1 you used in the morning. in any case, this is a convoluted system that doesnt reap much benefit, since like i said, most people spend most on only the few categories. i also havent gone into the effort required to sign up for 10 citi cards and product change/downgrade to custom cash. given a multi-year effort, anyone is better off just signing up cards with good SUB, which trumps the 5% from custom cash.

furthermore, no matter how many custom cash you have, it doesnt change my original point that there are still use cases for double cash and chase freedom cards.