Directly, and not convincingly at all. He presents just one use case, which, coincidentally, is the only one that casts the service he runs in a really good light. There are other use cases, like several email users leaving Gmail altogether, escaping from what he calls "the worst of both worlds". And his alternative? Using the centralized service (preferrably, the one he runs), because, he promises, this one will be totally different, aha.