There is not 1 benefit to American citizens by having illegal immigrants in the country.
There isn't a single illegal migrant neighborhood that is a desirable place to live. Public schools are negatively impacted by the presence of children of illegals. Wages are kept low by illegals willing to work off the books for lower wages. Hospitals are stuck with massive debt for treating uninsured illegals. Many young male illegals join dangerous gangs.
In Europe, women no longer feel safe walking around in towns where their ancestors have lived for centuries.