In the US credit cards are the most common, which typically charge the merchants a 3-5% processing fee, so I’ve seen more and more places offering a discount for paying with cash.

Italy: transactions under 10€ rarely (if ever) have any fees.

Over 10€ is still rare for them to have any fee, but even if they have, they are usually so small that nobody considers them. In fact, if someone prefers cash, I automatically think they want to avoid taxes (mostly VAT).

In Germany this is also the case in the surface. In reality it's just easier to avoid taxes with cash

In Poland I know that's illegal at least. A lot of shops tried to oppose cards, but law was more and more enforced. If shop proclaimed they service cards, they had to service them like cash - without any weird requirements.

What convenience does a digital wallet add that a card cannot do ? isn't a digital wallet way less safer given that mobile platforms are the least secure ?

It's painful to watch, ngl