That's true, all these use cases have always being met with bad endings for investors while the team moves away with the funds generated. However from the list, I can say based on my own understanding that gold backed tokens tends to be the worst as I have not seen any which is working nor any which is actually living up to expectations. In the case of deflation tokens, I think there are some platforms which uses it, such that when tokens are used for services the supply tends to reduce nevertheless it was still leveraged on by scammers to achieve their aim. Therefore what this shows is that, before one invest in any project, one should study the use case and make sure it is something that can work.