Inspired by current events, and the ongoing problem of too many old people and not enough young people creating a burden on pension/healthcare systems in Asia and around the world.
For starters, I can see that not having to pay out so many pensions would be directly related to freeing up more money for the government to use for other things like infrastructure development and overseas expansion (In this hypothetical situation, we'll call this the cough "Sash and Street" Initiative cough)
As a side note, in the snow country of Japan hundreds of years ago, poor families supposedly had the tradition of oba-sute (姨捨--lit. "throwing away old woman") in which they walked the elderly in their family deep into the mountains and abandoned them to die, so that their food stores would last the rest of the family through the winter. I'm imagining this on a global scale.
Note: don't do this. That's what bad guys do.