LR:
JW's have usefully made themselves guiena pigs in bloodless surgery. Every pint of blood that isn't wasted needlessly is a pint of blood available for trauma victims who really need it. I am sure the techniques used on JW's have spread.
Their aggravating preaching work and resultant persecution has improved freedom for everyone.
They've also created a lot of home businesses to facilitate their pioneer ministry. Some have been so successful in their business models they don't have time to preach and have left the organization. What is the value to an economy of entrepreneurial activity.
Their emphasis on verbal skills has improved the communication skills of hundred of thousands.
Also who else would buy so many four door cars?
Christian Scientists have cult like features. Their refusal of any medical care has provided a lab for testing mind-body relationships in disease.
Do you want to find out the long term effects of caffiene - you've got an excellent control population in the Mormons.
If a cult is too deadly it will die itself.
You cannot be sure what valuable thing the whirlpools in the chaos will produce.
As individuals we can just as easily be damaged by the so called conventional organizations. What about those who have invested years of their life in a company only to have it go bankrupt and they lose their pension? All organizations have the power to impinge on your personal freedom because all organizations require some sort of subordination for the sake of a greater good. People need to learn how to protect themselves in any organization