An simplified evolution of economy:
1. Barter was commodities traded between individuals.
2. Money was decreed, issued, and valued, still ultimately by an individual used to trade commodities.
3 Bitcoin is the first socially decreed and issued money that is itself a virtual commodity with as yet undetermined value.
N. The next evolutionary stage will probably be algorithms that intelligently manage resources. Bitcoin may be the first stage that allows this to happen because it is decentralized, scalable, secure, and yet completely transparent.
You can already create programs that trade commodities without the need of money. But using money is convenient because it simplifies a lot the economic calculation.
For example, when you are planning something is easier to think in terms of just one thing, money (I need 300 bitcoins for this project), than a list of commodities. It also allows for unexptected contingencies (I need 250 bitcoins plus 50 to be safe). Money is useful and makes things easy helping human development. Thats why we use it.
Also, your point 2 is wrong. Money is not decreed. The decree comes later when people is already using it as a means of creating a monopolly. Gold, silver, etc... were socially selected.
I won't get into the debate about who issues money. Historians and coin collectors might have better opinions about that.
Of course we trade commodities with money, but fiat money has problems with local currency regulation. I wasn't aware of "programs that trade commodities without the need of money." This electronic barter is common?
Here's my point about the next step in the evolution of money. At some point, this technology will eliminate economic tribalism. Efficiency and security will replace trust. This technology will help create a global economy independent of nations, because it eliminates the need for trust of tribal leaders.