More money, more income. That's why flood of foreign money is good for a university. But, it is a fallacy to think that this has no cost.
In my experience, the large influx of foreign students are typically at the masters level. MS classes are typically (not always lol!) more advanced than undergraduate classes. So, you need more qualified instructors, such as your tenured/tenure track faculty to teach them. When you take T/TT faculty out of undergraduate classes and replace them with teaching faculty, you lose a lot. (Let me know if you need what's lost to be spelled out.)
In my experience, the large influx of foreign students are typically at the masters level. MS classes are typically (not always lol!) more advanced than undergraduate classes. So, you need more qualified instructors, such as your tenured/tenure track faculty to teach them. When you take T/TT faculty out of undergraduate classes and replace them with teaching faculty, you lose a lot. (Let me know if you need what's lost to be spelled out.)