Living with people of different ethnic identities allows for an opportunity to know more of the other ethnicity- their culture, food, practices, etc. I have lived with people of a few different countries and religions and have found this to be an enriching experience.
This arrangement also broadens one's horizons and thinking. Many times conflicts arise between nations and states because of intolerance of other ethnicities' lifestyles or habits. It is only by living together that one gets to understand the reasons behind how other people might act. This generates tolerance and empathy- which are essential requirements for harmony between peoples of different ethnicities and cultures. Living with people of other ethnicities will also ensure that racial groups are not formed (or at least are not radical).
At a more personal level, food choices are extraordinary and so are music and clothing (I had flatmates during college). Overall, it is one of the most educational experiences of one's life.