The OP has a point; carrying lots of cash is quickly turning into a crime. Cash is effectively untraceable. Law enforcement does not like that so having a lot of cash is viewed with the strong suspicion that you are engaged in illegal activity. If you want to deposit more than $10,000 in a bank you have to explain yourself by completing a currency transaction report. Similarly, if you are coming from abroad, there are limits to how much cash you may physically bring into the U.S. without having to explain yourself (why do you have it? Where did you get it? What are you doing to do with it? Why aren’t you using another instrument like a cashier’s check or wire transfer? etc). Many people do it, but it is technically illegal to store lots of cash in a safety deposit box in your own bank. Until very recently it was fairly common for an average person to have a safe in their home and store cash in it. One can still buy and use safes, of course, but these days your average safe can be broken into or readily stolen. Most people feel better about storing money in a bank. I keep a small amount of money in my car, and a few thousand dollars in cash at home (not in a safe), but the days of keeping tons of cash in or under your mattress are long gone.

Some time ago, a long time friend came to me in (what must have been) serious trouble. He told me that he needed some cash/money fast, but he could not tell me what it was for nor could he say if or when he would ever pay me back. It was not a small amount of money. Guess what I told him...