The benefits are not purely monetary - raising the quality of an area due to investment that otherwise would never come in is an enormous benefit for people already living there.
That isn't too say throwing money at a bad neighborhood is guaranteed to succeed but it gives a far better shot than letting the area simmer in stagnation.
That isn't too say throwing money at a bad neighborhood is guaranteed to succeed but it gives a far better shot than letting the area simmer in stagnation.