The leaders of the Watchtower cult have elevated themselves to immortal life alongside Jesus and Big J (at least they imagine they have!) while at the same time they beat the followers into pathetic dependency on their every word. They load on the guilt as a motivator.
Destroy a person's self esteem and they will be easily manipulated. If an 'authority' claims to be from God, the person with low self worth will more easily be taken in by it.
Where is the sense in choosing to become a "good-for-nothing slave"?
Isn't the answer: only if you already have low self esteem.
It will confirm your identity as inadequate and try and make a virtue of it. Like the masochist you are you give your life to "The Organisation"!
But everyone who does never achieves or receives anything in return and dies disappointed.