To add to your (correct) answer, world's economy has to based on growth for physics reasons. In the real world, almost all things that we produce slowly depreci

To add to your (correct) answer, world's economy has to based on growth for physics reasons. In the real world, almost all things that we produce slowly depreciate due to entropy. So to even maintain the living standard, you need constant production, and thus constant investment. Deflation doesn't incentivize investment (which is an irreversible decision), so the only alternative is, in the face of risk, (small) inflation.