The biggest reason foreign workers come to USA is to remit dollars.
Indian programmers in Silicon Valley have a saying: “Loot and remit, die for dollars, outfox the Yankees”.
Not just illegal aliens, but all foreign workers come to the US to remit dollars. Dollars are worth a king’s ransom in the 3rd world.
Many H-1B workers return home to India after 6 years and retire like kings on $400,000.
In China, remittances are illegal.
“Columnist Michelle Malkin is calling on President Trump to “shut down” a Federal Reserve program that profits off remittances sent to foreign countries by illegal aliens”.