He had asked my dad to partner on the deal, but it was fortunate that he didn't because it was a loser for several years, compounded by a tenant falling asleep with a lit cigarette and burning part of the building down. 

I'd also see if you could sell them on 0.5% per month interest (which amounts to 6.16% per year compounded).

...easy, because all cash buys:1 - ...increases how much the property costs the investor,2 - ...if the property is negative cf with leverage, you can pay for all of your negative cash flow upfront3 - ...It increases the risk you have in the property4 - ...it limits the amount of properties you can gain control over5 - ...it reduces the value of your equity6 - ...it eliminates all of the free equity you get from appreciation and the tenant's rent7 - ...it eliminates the power of compounding from your REI8 - ...it dramatically slows down your ability to quit your job and replace it with rental cash flow9 - ...it takes you longer buy your next property10 - ...it delays the date of profit since your accumulated cash flow has to equal what you paid for the property out of pocket bore you can record any profits11 - ...it,...wait a minute,..., you were asking for the reasons where buying all cash was a GOOD idea. 

Warren Buffett says it’s one reason he was able to amass such a huge fortune.The key to compounding is to let it work over many years.Just look at the chart below… It shows the value of an account growing at 10% per year over 60 years.I call this the “hockey stick” chart because the money grows slowly for several decades, then really picks up speed after about 40 years.If you don’t interrupt it, compounding produces a fortune.Let me know if you know where you can put it and never stop the compounding?

And, at the same time, Brazil has undergone a big economic crisis, which has had a downward effect on real estate prices expressed in reais, which has compounded with the drop of the reais against the dollar.

When they pull back, the effect will be compounded due to the sheer size of their appetites and the hole they can leave in your business or market when the buy-side turns off.

This probably was also compounded with decreasing real estate values in general. 

Compound interest is the 6th wonder of the world.

If you're contributing to your current employer's 401k plan - and they are matching those contributions - you'll be losing out on the compounded value of that free money. 

Its the growth.The RE growth is compounded with leverage.  80% LTV with modest 4% property appreciation (which is low for San Fran) is 20% return from the property appreciation.