If you hold a rental property long enough it's hard to make no return/negative return just because of the nature of markets and fiat currency. 

Investing in currencies & the stock market is the same as playing slots in vegas. 

Paper currency got its start as little promissory notes to pay gold, and then because the notes were more portable than gold, people started using the notes as money instead of the gold itself, which is why you sometimes see references to "one dollar notes", etc.A seller may or may not accept a promissory note as payment. 

Does this not work for properties bought with foreign currency?

Started back in 2010 when the US dollar started to get weak and foreign currency was gaining some strength.

Fortunately for us most of that crowd is into crypto currencies these days. 

If currency goes to heck - and the new currency is marbles - I feel someone, will pay me marbles to live in my dwelling.  

Less currency risk and conversion costs.

In short order you are paying off dollar notes now worth 75 cents with inflated fiat currency now worth $1.50.

Time is your most valuable currency.