I used to think the same way, then I started carrying my own wallet and using it everyday. I loaded it up with 20-30 cards and then a wad of dollar bills, and discovered the damn thing didn't fold! Plus, with the credit cards smashed in there, it was virtually impossible to separate one card from the rest. I was unloading 5 cards everytime I needed to use just 1.
Your design is completely different from mine, so maybe it works better with heavy materials. But if you haven't done so already, definitely build one for your own use, carry it everyday, and make sure it works as well as you think it does! :angel_not:
Alex