[whatshisface]

1) Money ends up in the local economy

2) Money ends up in the local economy

3) Currency deflates, making all owners of currency richer, and as long as nobody expects deflation to continue, stimulates the economy.

[iso1631]

In the case of (2) there is a new bridge which increases productivity in the long term

In the case of (1) there is a no bridge

You've already disproven your "All expenditures stimulate the economy equally" claim with your explanation of (3)