If he is concerned only about debasement then he should be very concerned about the need to self custody. Every bank in the history of the world has debased the money it held on behalf of its customers. Self custody is the only tool we have against debasement. If all the bitcoin was held on exchanges those exchanges could sell has much paper bitcoin as they wanted and it would make bitcoin worthless, even ignoring the lake of censorship resistance and seizure resistance leaving the money on an exchange would cause.