There is obviosly much strength in diversity. I dont know if it should need to be a thing you intend, it should more or less be the natural order of things.
Would you rather live in a town with 15 of the same kind of restaurants, or a town with 15 different styles and types of food?
I mean, I love steak and eggs, but sometimes I want prime rib, or smoked ribs, or lazagna, or fish fry, or thai food, or korean bbq, or a jewish deli, or some grecian style braised octopus or gyros or pizza or tacos or pancakes or vindaloo with naan or pindi chaana or briyani or gumbo or jambalaya or oxtail soup or jerk chicken or mexican goat stew or arroz con gondules etc etc etc ...
I want to live among people with lots of different backgrounds so I can have an opportunity to enjoy a little bit of what they bring to the world. Its purely greed, I will reciprocate by whatever means I have to share a little bit of myself.