'Encouraging money to be invested, by motivating people via inflation, is a good thing overall because it puts wealth to work creating jobs and stimulating economic activity.'
No he didn't. He argued that we need inflation to stop hoarding of money and make people spend their money and create activity in the economy. This is important because in the economy as a whole TotalSpending == TotalIncome
He said that as a society we benefit from inflation because as individuals we are forced to invest our funds so that individually we can avoid the effects of the inflation.
I'll reword it for you:
'Encouraging money to be invested, by motivating people via inflation, is a good thing overall because it puts wealth to work creating jobs and stimulating economic activity.'