Generally, it brings new perspectives, and learning which you cannot get any other way. Also makes life less boring.
One way I made life interesting for myself is by working in all corners- and centre- of India, from Lucknow to Calicut and Bangalore to Indore. A senior friend once told me I wouldn't survive North of the Vindhyas. But I did survive for a limited period- actually a long time in Indore.
All universities must strive for diversity in their constituents- students, faculty and administrators. This difference is striking when you compare an average American University with an Indian one. I learnt by interacting with Chinese, Nigerian, Iranian, Turkish and Portuguese classmates during my Ph.D., in addition to American students.
Also, in my American workplace later, I had a Venezuelan colleague, as also a Korean, in a faculty of size 12.
It would be a nice goal to have a gender diversity goal, in addition to other kinds- regional, ethnic, religious etc. in any cohort of students, if possible. It makes classes engaging through peer learning too.
I have also been to conferences that had multiple nationalities participating- Sri Lankans, Bangladeshis, New Zealanders, Canadians, Vietnamese, Australians and so on. Sometimes held in Singapore, or Japan, or Sri Lanka, or Vietnam.