It's always interesting to me when people talk about the value of the dollar in terms of sales of property here. There is a connection but it isn't very meaningful. The value of homes here is listed in US dollars in order to keep consistency of property values in a place that once used the dollar to value it's currency. Period.
Real estate in a volatile economy is NOT a sound investment. That doesn't mean you can't make massive cash, but you have to wait until the market drops and buy then. The market here, though cash based, will experience a correction if things have risen too fast. What is too fast? The median value of property can not increase incrementally higher than median income or it will have to correct. It has begun to here. It won't correct in the same way it did in the states because most people here don't have mortgages but it will correct. No matter what the dollar does or how many expats move here the people who determine prices over all will be Argentines. There are more of them and there always will be.
I sold professionally, and made money in personally, Real estate in the states and it is interesting to me how people choose to buy. If you are an investor, the market is only beginning it's correction now. How much it goes down NO ONE can guess. When markets are high is when people belatedly get interested. They hear stories of people saying they made huge money or bought low and now it's worth blah blah blah. A house that isn't for sale is worth nothing. Look at the value of the home, ask if you can hold it 12 years (the global average for real estate cycles) without making money on it (you never know what's going to happen to impact tourism) and then make your choice based on your best belief about what will happen.
Investing in real estate is a gamble, but if you are going to do it in SA, buying in the regions largest city is the closest you'll get to a guaranty because people will always need to have a home in the city, no matter what else is happening.
Suerte