My ideal wallet would be no wallet. Cash makes my wallet too thick. I keep some non-daily cards in there (like debit card, Rx card) because I’m too forgetful to manage continually adding and removing cards. There are phone based solutions but I don’t want to be reliant on a charged battery for absolute essentials. Cash is funny because I am super hesitant to break a large bill, and then very eager to get rid of the smaller ones, and where I live, it’s generally a good idea to carry one larger bill as a fallback.