A currency with inflationary pressure incentivizes investments into new enterprises. A currency with deflationary pressure, instead, discourages investment outside of banking.
Here's why. With a slight inflation, money slowly loses value. Even if you put it in the bank and earn interest, it loses value over time. So the rational thing to do, if you have a lot of excess money, is to find places to put it where it outperforms inflation, where it has a chance of not evaporating over time.
With deflation, money is instead guaranteed to be more valuable tomorrow than it is today. Sure, you could still try to invest some of it to try to outperform the gain you get from deflation, but it would be completely rational to just stick all of it in the bank, and live the good life forever, as your money automatically becomes more money (because its buying power increases), every day.
Why is there so much money managed by VC and Angel funds? While not the only reason, I'd claim it has a lot to do with inflation.
And, of course, I'm making things more b&w than they really are. Both massive inflation and massive deflation are really bad things. Currency that stays largely stable, or that deflates/inflates slowly over time, seems to work out fine.