Currency in the real world has many, many backups. For example, if I forgot the PIN number to a very old bank account that I later find a long lost relative recently put hundreds of thousands of dollars into when they passed away, I have other avenues to recover access. They might be annoying or require work (getting an affidavit, multiple forms of ID, etc) but it's not irrevocable in the way that a strict definition of bitcoin is.

A bank account is not currency. Cash is. You can still put cryptocurrency in a bank if you so choose.

It's a lot harder for the average person to lose 1 million dollars in cash than in Bitcoin because humans naturally understand the exchange of physical objects.

If I have a duffel bag of money, it is obvious that physical possession of the bills means I can access its value. Anything negating that possession would cost me my money. I should probably keep it away from open flames and water; but it's not going to spontaneously combust. A thief would need to physically take the money in the duffel bag for me to lose the value.

Meanwhile if I store Bitcoin on a USB drive the drive might randomly fail and I lose all my money (because I'm actually storing a key to access it) even though I still have the USB stick. The solution is to back up my key in multiple places simultaneously, which doesn't make sense to most people (how can money be in two places at once?)

If I plug the USB stick into the wrong computer, someone can steal all my money (because they can find out what the key is) without me ever losing the USB stick.

Virtually every human on Earth understands the notions of object permanence and that objects can be exchanged for other objects. This is intuitive from evolution and actual monkeys can comprehend physical currency.[1] I don't see how cryptocurrency can be on that level.

[1]. https://www.zmescience.com/research/how-scientists-tught-mon...

The concept that this file is the password to the money isn't too complicated. The money isn't in two places at once, the file's the password to it.

It’s impossible to comprehend to most people.

Except reality isn't so ... digital.

In reality I've found a lost wallet and helped return it to its owner. At least twice, actually. Both times because there was an identifying name in the wallet.

Then there's the time as a kid when we found $60 on the floor at a department store, and turned it over to lost&found. I remember it because the store had a policy that if cash hadn't been claimed for a month, then the person who turned it in got it. Which we did.