One major benefit to 3rd party shopping carts is that they can cleverly adjust the payment amount and currency symbols based on where the potential customer is on the web. I think this could be a huge help. Currently, for instance, what happens if someone in Australia visits my (US) site, and my price shows $19.95 (usd)? Are any of you using any creative methods to auto-show amounts in the user's currency to increase sales?
I believe it is not to increase sales, but to earn more $$$ on currency exchange. Exchange rates offered by such services are not good! I would better keep currency exchange to my bank (that issued the card)
Doing that result in foreign exchange fees. Bank exchange rate are not really competitive as one would believe it was.