I know that the 10% would go into savings, which in a normal normal interest rate environment would be lent to homebuyers, homeowners, small businesses, etc. Banks would lever that up (they're only required to keep ~10% in reserves) and as borrowers spend that money, it generates more deposits of which 90% can be lent again. It's called the money multiplier. The banks would earn interest margin and savers would earn interest (what a novel concept) and while some of those loans may fail, on net the businesses earn a positive return on the projects for which they borrowed the money. It's not a theory, it's imperical fact. But our system of near zero interest rates, never ending QE and Keynsian stupidity perversely disincentivizes savings. And idiots on the left think that G is as or even better or as good for an economy as C, I and X despite literally mountains of evidence that proves governments are extremely poor allocators of capital.
What do you think would happen? People would stuff it in their mattresses? Or spend it on voter suppression campaigns?