Posted November 12th, 2017, 05:18 PM
We did "around South America" on the QM2 in 2009. (According to DH: best trip ever!!!)
Never spent a penny of local currency. Booked tours through Cunard, which included lovely luncheons (great food with wine/beer).
We didn't venture out on our own and felt safe and happy under Cunard's wing.
Bought a couple trinkets near the dock in Chile and paid in dollars. Bought paper flowers in Mexico (at a market further from the ship) and paid in dollars.
Most "nice" shops and restaurants, world-wide, take plastic. Most vendors near ships (full of Americans) take dollars.
I think your currency needs will depend on what you like to do, but I can tell you: it doesn't need to be complicated.
Happy Sailing! Jimmybean