One downside I have experienced is that foreign debit cards, such as Charles Schwab VISA debit card, run on the credit system here in Argentina and thus are not accepted.
It happened to me once in a place showing the sign 'VISA debit card only', and when I handed my VISA debit they tried it with their POS but it kept going on the credit payment system. Eventually the store manager let me pay anyway (the POS device can accept credit transactions, as well) but warned me they won't be accepting my card ever again. Nice.
This has happened also in the US with an Italian debit card, which overdraft. I never thought it was possible to overdraft on a debit card, but it did!
