What benefits?
This "diversity" thing is a bunch of bullcrap. It has no benefits whatsoever.
I challenge you to name one - and I mean it, just one concrete benefit of this so-called "diversity".
Here's a benefit (a few):
A.1. You learn about cultures that you normally wouldn't, helping to create empathy for those cultures
A.2. Without learning about other cultures, it's too easy to think your own is better
A.3. If you, or the general populace, has a notion that your own culture is better, then during war, it becomes morally easy to destroy a conquered people's culture and supplant your own
A.4. Destroying other nations' culture is generally considered a bad thing
Scenario A is exactly what the Japanese did. They had a very insulated culture.
B.1. You get to try foods that you normally wouldn't, when the immigrants come to your country and bring their recipes.
C.1. New ways of thinking can be introduced by immigrants in the scientific fields.
D.1. Products that are familiar in one culture can be brought to a new country, where those products might benefit the new nation.
I can't think of any others at this moment.
Overall, the notion of forced diversity that is common in politically correct thinking is a load of crap, in my opinion. "Diversity" has some benefits, but forcing it on groups is a load of crap. (I've dealt with forced diversity here at the office; it's totally stupid.)