Well, in an ultimate sense it defeats inbreeding. Beyond that, raises the threshold for variety, new traditions, chance for trade---human society is about as social as nomadic in some respects.
The trick is "integrating" the nifty parts of your home culture with that of your new host country---even basic things like new cuisine can serve as fertile ground for understanding and progress economically and otherwise. Popping into somewhere new to just try to create a mini-version of the place you've left or fled from though, not trying to learn the language, etc----far less workable.