It's foolish besides--speaking engagements, etc. take away time from actually producing creative works. It's the sort of miss-the-point silliness often espoused by the anti-IP sorts: "spend an incredible amount of time doing X to maybe, if you're lucky, sell a marginal number of Y, where Y is totally unrelated to X."
It's silly and a misallocation of a wtiter's resources to take away from actually writing to hit the speaking circuit.