Why would a small economy collapse if more and more people would be using cryptocurrency? Remember that people will be using cryptocurrency to buy local products and if this can be done then the wheel of commerce will even be enhanced and maybe the market can be expanded. I am sure that there would be people that can be disrupted and this is just natural as businesses do come in and go out of business if the market can be shifting. I would say that the use of cryptocurrency can be bringing in fresh ideas, new products and the economy can be refreshed. However, it remains to be seen which of these two scenarios can happen when applied in the real world, though am so optimistic that cryptocurrency can be helping rather then be an agent of destruction (or collapse).