Brain drain to the US helps the US, yes. The key word there is the brain. What doesn't help is taking in unskilled and manual laborers; that only creates downward pressure on wages and upward pressure on housing prices and other scarce resources, even before we get to any correlation with crime.

Countries with a highly successful immigration system, notably Canada, do it by being highly merit-based, for education and professional skills. The US hasn't put together any significant plan for that. Trump briefly tried proposing merit-based immigration in his first term, but it was quickly shot down with all the usual accusations of discrimination and so on. The US kinda unofficially does it via H1-B and O-1 visas, though that's only for employment and mostly not for permanent residence.