> absolutely awful usability compared to the Euro

In what way? One unpleasant discovery I made in Portugal (and also saw to some extent in Spain) was that ATM’s - every one I could find, including those that were bank-owned at physical branches - had a limit of EUR200 per transaction regardless of my own bank limit (at USD1000/day, that should have been at least EUR800).

And while convenience stores, fast food, etc., won’t take a bill over $20 (which is understandable but really a trifling sum when you consider inflation - it’s a fast-food breakfast for three people), many other businesses are happy to do so. Nothing above $100 is in circulation anymore, and inflation means that $100 in 1980 is worth over $400 in today’s money even by government figures. A $20 bill 45 years ago was worth almost $100 in today’s money. And, of course, cash declaration rules have not updated the amounts to reflect this.

I went last year to Lisbon and Barcelona, from Brazil with 0 cash in any currency.

I had a debit card with some hundreds of EUR already charged, but I ended up using it with an NFC enabled smartphone.

No issues at all, even going in far places outside Barcelona. Everyone very receptive in BCN.

I looked at ATM terminals and they seemed full of rules and complications. I tried to get some cash just to collect the notes as a souvenir, but I gave up.

Again, everyone accepted my NFC enabled smartphone, I tested my debit NFC card and my local bank CC NFC card as well

So I think ATMs present a lot of friction for sure.

Same this year - I went through Spain, France, and Portugal last month and did not have to take money out of ATM for anything including eating, shopping for groceries, paying for gas or sightseeing.

ApplePay connected to my no forex transaction credit card earning 3% cashback covered 95% of these transactions and a few times I had to use that credit card directly.

How did you manage without cash in France? Many places here don’t accept anything but cash for amounts less than 5 or 10 Euros. If I just want to buy a coffee or a baguette, I often need cash.

I spent a few days in French Basque Country and restaurants and fresh markets all accepted credit cards and Apple Pay.

I was traveling with family so spending limits were higher than 5 euros

Okay, but OP specifically said that USD are inferior to EUR for cash. Never had issues spending with card in PT or ES.

> that US cash has absolutely awful usability compared to the Euro.

Euro bills differ clearly in color and size, which means they are quickly identified.

Also the Euro coins differ in shape and size quite a lot, which is easy to identify blind even when handled individually. More than U.S. coins which are more similar.

I don't know about an objective difference caused by the fact that 1€ and 2€ are coins and bills start only at 5€ whereas the one dollar coin isn't much used in favor of the one dollar bill.