OK. So it is as simple as that. I can pull on that thread. I get that flipping a coin 256 times, or using dice as an alternative (ideally roll 256 dice and convert to binary) is pure raw entropy. Cards can provide the raw entropy but the mixing process to get there is complicated and provides many o...

Seven card shuffle and a table shuffle will suffice for enough entropy. I’m not saying to run this for your actual seeds!