Unironically, I bought one that is basically that lol. I only carry cards. No cash, no coins, etc. Even when I did carry cash, I just folded it and kept in the back. The main issue is that your cards rub against each other when you're pulling them in and out, so you can potentially screw up the chips on them faster. It hasn't actually happened to me though beyond cosmetic damage. Fits a lot more nicely in my front pocket so I don't have to sit on anything.