I just finished a mystery based on forensic anthropology. The author pointed out that anthropologically there are three "types" of people: caucasoid, mongoloid, and negroid. These differences are structural: differences in bone structure and in hair follicles and don't really have anything to do with country of origin, just genetic heritage.
Not everyone in Africa is actually dark skinned. There are "white" Africans. And if we're really going to get into it, true Americans are mongoloid (Native Americans are more closely related, genetically, to orientals than occidentals). So what exactly does that make me? I'm a Dutch-British-Irish-Scots-American. What a mouthful, and why? Or I'm an English-American (because I am a citizen of both the UK and the US). It's all just too confusing for my poor muddled brain.
I like the efficiency of "white" for caucasoid and "black" for negroid because you reduce a word of 2-3 syllables to simple one syllable words. They aren't particularly accurate (nobody is really "white" or "black") but what the hey, people generally understand what is meant, they are easy to say and easy to spell and not particularly offensive to anyone so far as I can tell. I don't know a good shortcut for mongoloid.