"For those with excess money, inflation does encourage investment." If they have their savings in a bank account, it's invested anyways via lending so inflation doesn't change the amount invested. What it can change is how wealth is invested, e.g. high inflation causes people to abandon the currency as a store of wealth - you get people buying and "hoarding", say, appliances they don't need as a store of wealth whose nominal ROI is higher than bank interest on savings accounts.