Tax Free havens specialize in Captive Insurance Companies- Watchtower is certain to be doing this scam.
They have millions of dollars so they self-insure with a company that they themselves own .
They tell the poor slobs at the kingdumb hall that they need to pay for insurance every year, so tens of thousands of congregations pay millions of dollars year after year and the Watchtower gives the impression they are forwarding the premiums to an insurance company nobody has ever heard of.
In fact the yearly millions go straight into one of their own bank accounts which appears to be an insurance company with only one "customer" - themselves.
The advantage of off-shore is secrecy. Give some of your cult friends a credit card based on the off-shore account and no-one in another country will ever know as the paper work all goes back to the off-shore phony bank.