If I got an extra $100 or so on my paycheck, it would have very little economic utility. It would just be added to my pile of savings.
Nonsense. That's great that you'd save the $100, but even if you do that it still has economic utility, presuming you're putting it into a bank account. It then gets lent out to businesses or reinvested into the economy. The bank isn't sitting on a giant pile of money.