I hope before we quit funding the defence industry there are jobs for laid off military to go to that pay as much as their current jobs and I hope if we have a domestic disaster, there is someone available to help clean up the mess and go to people's aid.
If you don't mind sinking deeper into debt it could be used to develop usable products. Just for example the Colorado Shale deposits could be ground and used in place of regular gravel just because once it is in place the wind doesn't blow it into dust. Initially more expensive but once in place it is good for 10 years before a touch-up is needed. In that 10 years 50m yds of gravel have been saved and 3x that in costs involved in laying it here and there.
Once something is 'built' you get to sit around and enjoy it. Once everybody is getting their basic needs it is time to move onto leisure activities. Hopefull those low interest loans would mean snow skiing resorts would multiply into 1,000's worldwide rather than the few 100's of today.
Seriously look at what the US National debt has paid in just interest since the creation of the Federal Reserve .