If you marry the wrong husband, it's helpful to have a items you can sell in order to rebuild. The costs of lab grown diamond vs. natural is like a 60% difference. I understand wanting a real diamond for such an odd contract as marriage.
No doubt, and to tech folk like you and me, it's a tiny amount of money but in the nightmare situation of trying to rebuild after an abusive marriage, the price of natural vs. lab grown makes a difference.