Some kinds of consistency aren’t always uniformly valuable, either: a site that serves doctors, patients, and insurance providers, for example, will probably use three different voice/tone guidelines for the three audiences, and another for content intended to be read by a general audience. That’s healthy, reader-centric consistency. On the other hand, a company that permitted each of its product teams to create widely different kinds of content is probably breaking the principles of consistency for self-serving, rather than reader-serving, reasons.