You need to physically transfer cash, and this is why it's difficult to use for things like ransom.

You know what makes it really easy to ransom a hospital during a pandemic? Monero. You know what makes it easy to ransom a school, leaking personal information of children in the process? Monero.

I am not sure about the 'hard to trace' part. they could track the serial numbers on banknotes, for example when an ATM is dispensing the banknotes. Also there are people who persue the tracking banknotes as a hobby: https://en.wikipedia.org/wiki/Currency_bill_tracking

It's comparing apples and oranges though isnt it? Monero is fungible, cash is not.

Except for the de minimus overhead of making-change/breaking-big-bills, physical cash is usually described as 'fungible' in the sense meaningful for economics: each $N is completely equivalent to any other $N – na matter its history or how the tally was subdivided/recombined over time.

That's not what fungible means though. When you start printing numbers on them, they're no longer fungible.

Perhaps pedantically from a particular viewpoint, & if banks used a blacklist of certain bill numbers.

But to financial economists, cash is a textbook example of a ‘fungible’ thing.

So a statement like – “Monero is fungible, cash is not.” – implies you’re using peculiar definitions.

Fungibility means that two things are mutually interchangeable on all levels.

I cannot take cash into a bank that came from a heist or a covert drug buy from the authorities for example, I'd go to jail. The term 'marked bills' exist because cash is not fungible, not all bills are equal.

This is the binary quality of fungibility. There are no shades of fungibility, there is no "well this is X's definition of it".

You are free to write as many words as you’d like on your idiosyncratic beliefs, but the fields of law, finance, & economics, as practiced & documented, disagree with you:

https://www.investopedia.com/terms/f/fungibility.asp

(It is interesting to think of the ways traditional cash might not meet a physicist’s definition, or assumptions under which Monero might somehow be more fungible or less fungible than physical cash, on a spectrum richer than a pure binary. But if you remain oblivious to what the word commonly means to others, you’re failing a bit at communication.)

True, but the key difference is that cash must be physically transported.

Ransomware is largely the fault of those institutions not keeping backups and having atrocious security practices.