[analog31]

Having a well articulated purpose, and being "centralized" are two sides of the same coin. We can agree on a purpose for government money because it has been deliberately molded to specific purposes: A medium of exchange, short term store of value, and instrument of economic policy. We can measure its performance against those purposes, and in fact, that measurement process is part of the technology of our money system.

Not knowing the purpose of cryptocurrency is its purpose. There's nothing wrong with having a general purpose technology, like computer programming, that is adaptable to specific purposes on demand.