"we are going to go back to how people used to travel 50 years ago: with a lot of USD bank notes hidden in your hotel room or elsewhere ..."

Who did that?

Most people except for criminals and refugees used traveller's cheques:

https://en.wikipedia.org/wiki/Traveller%27s_cheque

I think some banks, like AmEx, still issue them.

People did that? I took one look at the fees and ... "no thank you", and took cash.

Yeah, if I wanted to pay the crazy spread on currency exchange, I’d use my credit card instead.

10 years ago I was still traveling with a bunch of $100 banknotes and reading blogs to find the most honest shady currency exchange place with good rates wherever I went. Fun times!

I even paid for two! iPhones in cash back then!

Today? I just stop by an ATM and withdraw some cash, everything else goes contactless on Wise.