A recent NPR article highlighted a reasonable strategy to hedge risk of outliving your savings. But it's dollar-based payout system will leave many seniors paying the bill if the dollar declines. The dollar is the undisputed world reserve currency, for now, with many smart people at the Federal Reserve managing it. However, new challengers have emerged to the dollar. These challengers are backed by advances in mathematics and cryptography. The challengers use computer algorithms to manage them, instead the 'little grey cells'. The challengers are fundamentally more efficient, adaptable, and less arbitrary than the dollar. The one saving grace, so far, is that the dollar has been more stable than the challengers.
Investors buying a 15 year deferred fixed annuity are betting that they will: (A) be alive and (B) dollars will hold their value until they die. That is a rather large bet in favor of the incumbent. If the dollar transition happens while they are alive, they are going to be impoverished.
What is really going to drive this transition? The IMF has detailed that these challengers "... will likely be more widely adopted in countries with less credible monetary policy." (source) Now how could that be the US dollar? Look at what happened in 2008. Too big to fail and implied federal loan guarantees will happen again. Look at how the Federal Reserve manages the currency. Two words in a long technical talk cause major ripples in the economy. Look at the way the Federal budget is managed. History tells us there are three ways out of a debt hole you vote yourself into: Inflation, Haircut, or Monetary unit change. None of those ways works out well for people holding dollars or expecting to receive dollars.
Maybe you think you will pass away before the transition. For me, I am in my 30's. I am going to have to live through it. I am betting on the challenger.