You probably can't have a stable global cryptocurrency without a central bank. Bitcoin fundamentally cannot work for credit because the risk to the lender is ridiculous.

Macroeconomics doesn't work in diverse economies if you can't partition off areas of the globe and create friction at the borders for trade (with monetary policy).

The same products and services need to have location based costs to ensure local economies can function.

Now complete isolation is worse that perfect free trade, but there must be a balance. Lack of balance brings wealth concentration, poverty, starvation, and war.