Race: When is it important?

Recently, I had a discussion with my family regarding the premier of Frozen. I had found out that Jelani Alladin, a black man, had been cast in the role of Kristoff, which I was pleasantly delighted by. However, there was some debate in my family regarding it because of the fact the story technically takes place in Scandanavia. It got me wondering about when race actually mattered to a role. After all, minorities weren't allowed to play them selves for years, and white people dominated cinema and theater. However, we are finally starting to progress, and more and more minorities are finally making it on the screen. However, many leading ladies in movies like rom-coms or drama are mainly white women, regardless of the fact that role could have gone to anyone. Many minorities have won for roles where only they could have played the part. So now I ask, when is race important when casting for a film, or in the theater. I personally believe that race in movies matters in one situation, whenever the race of the person is essential to the plot. For example, the movie Dreamgirls would never cast a white person in the role because the story revolves around a set of black artists trying to make their dreams come true in a predominately white industry. And I have seen moments in cinema that have personally been disappointed in the portrayal of the minority characters. I hated Flo in Pitch Perfect 2 because of how over the top stereotypical portrayal she was. I'm all about making fun of myself, but not like that. And considering many movies don't have race being the core plot of the movie theme, it's still a bit of a shock to see that many leads in rom-coms are white and when they aren't, they have to be an all minority cast. As someone of Mexican descent, it's sometimes difficult to look through rom-coms or other kinds of movies and one of the only leads of Latin descent is Jennifer Lopez. I notice that many minorities are just supporting characters. I was watching a Buzzfeed video, which revolved around women recreating these rom-com posters, and one of the ladies did The Wedding Planner, commenting about how excited she was when the movie came out, since it starred a minority woman. I have found that theater has become more inclusive, incorporating many roles for many diverse nationalities, and while cinema is improving, I find that it still has a very long way to go.