All it does is transfer money to the contractor doing the digging (in America's case, the military-industrial complex) while everyone else becomes poorer.

$8 trillion has been spent on the War on Terror so far. Like I said in another comment, that's enough money to build 80 million $100k homes, or reduce America's debt by 25%, or pay off all student loans, or build 400,000 KM of high-speed rail at $20M/km, or give every American taxpayer a one-time check of $48k, etc.

Every bomb dropped on Afghanistan or Iraq was money diverted from something else useful the US could have done.

Does it? So far millions of traumatised and in various ways challenging to deal with refugees are in Europe.

https://www.imdb.com/title/tt0372588/