When computerization gets to the point that we can compare and trade items and services and labor, based on their average value relationship as sported by the whole, worldwide, free trade process, then we won't need fiat or Bitcoin at all. All we will need do is jump on the computer, show what our job is, show that we labored so many hours last week (a showing that is placed there by collaboration with our employer), and we can trade our labor for whatever goods or services we need.
All of this will be encrypted in a blockchain of blockchains, of course. We will be able to remain reasonably anonymous, just like with Bitcoin. For our purposes, we need only see the first entry of an "address" into the blockchain, and the value attached to the last entry. Probably a computer program will be needed to generate the whole operation. It may not be entirely programmable by people.
Parts of the above are being done right now in airline comparisons, and product and service comparisons. The difference will be that there won't be price comparisons. Products and services and labor will actually become the new money. There won't need to be stated divisions of "coin" like a satoshi is part of a bitcoin. Everything will be expressed as a percentage of value of anything else. The whole operation will be entirely decentralized, yet it will act like centralization in the ways that make centralization beneficial.
That won't work. Work hours does not equal worth. How would I trade a 6 hour workday for a new computer? My 6 hour workday is just numbers, it's not like I'm trading an actual product that the seller can gain a profit off(After all, that's their goal, to get a profit). You will still need money.
Hey! I was talking in generalities. I don't have the system built. So, you work at Walmart. Your work hour is worth only 25% of a heavy machine operator's work hour. That's part of the way the system would operate.
A person would be a number in the system. He would be an encrypted address. His labor would be coded regarding the value that his employer uploaded to his address from the company he worked for.
After awhile, the way things are rated might change. Job pay scales might become more equal. Until it happens, we won't know what will happen real world. At least at the beginnings of it, people will still use fiat and bitcoin - Bitcoin is a form of fiat.
EDIT: When you check the airlines for prices on the Net, most are at least a little different. Direct value relationships can be also, even for the same product traded in different locations.