I don't think it's shame; just practicality. If I'm about to hand someone a large sum of cash, it's generally not practical to carry that in my wallet. Plus,

I don't think it's shame; just practicality. If I'm about to hand someone a large sum of cash, it's generally not practical to carry that in my wallet. Plus, that money likely came from, or is going to, someone who also doesn't want that money mingling with "their" money. (likely someone who will be dealing with several such envelopes) And, in general, you don't want to have more money than you owe in front of you, while you count out a criminal's portion. If you do, you'll quickly find that prices go up. There's also plausible deniability. Stacks of cash attract more attention and aren't as easy to explain away as envelopes. And envelopes of cash have the hallmark of the legitimate proceeds of a cash-only business 'on its way to the bank'. If the money is mingled with your own, that's a harder argument to make.