I think his point was that querying a structured data is better than grepping unstructured text. SQL vs Regex, for example. I get the impression that he didn't state what solution to use but simply that binary/structured > text/unstructured. He even says that Journal isn't his ideal solution and never will be.
He needs a log database, clearly. And when you put it that way, it's obvious why grepping logs is a nice, quick solution in many cases when you aren't getting "100Gb of logs a day".