While of course teaching others may be exactly the greatest utilitarian impact available, whenever someone's first and only move after coming to a new belief is to preach it, I suspect they're wireheading status or knowing-powerful-secrets (on top of my suspicion if they're seeking payment). If they were to actually test their ideas in practice, those ideas become more trustworthy - at the very least, bugs will be fixed, and their promotion will be more realistic and persuasive (if their ideas actually held up).

For example, some guru who sells a way of being happy and successful, may be happy and successful only because he gets the thrill of speaking in front of thousands of rapt listeners. If you take away his lecturing gig, what do his "highly effective habits" really earn him?