UTF8Type vs. ByteType Apache Cassandra

could you help me find out the reasons behind why "user" column family is compared with UTF8Type not ByteType and username with BytesType not UTF8Type in this article: http://www.racksp开发者_StackOverflow中文版acecloud.com/blog/2010/05/12/cassandra-by-example/

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No good reason. Today good style would recommend making both UTF8Type. It only matters for validation though; even if column ordering mattered (which it does not on these CFs) utf8 sorts the same as lexical byte ordering anyway.

Also: wouldn't commenting directly on the article be more useful for other readers?