I agree, physical forms of money (on the surface) seem more robust, but as a developer for more than 20 years, I'm biased towards code because (unlike the gold confiscation in 1933), I think obtaining everyone's private keys might be a little more difficult (especially if proper paper wallet creation procedures are followed). I have concerns about hardware wallets as well, but I'm currently giving them a shot.
I think risk is the enabler of courage. We could say fear comes with risk, but I prefer thinking in terms of risk having probabilistic negative outcomes which we want to avoid. No fear needed to have courage in managing risk. Based on my understanding of neuroscience, fear (and many other intense, primitive emotions) really does shut down the prefrontal cortex part of our mind which does all the thinking. If we have trusted facts, we don't have FUD by definition.
They will certainly try to take them over, but cryptocurrencies are anti-fragile by design. Taking them over, by design, is quite difficult. Due to the nature of open-source technology, it's also very difficult to do effectively over the long term. Some fear bitcoin was being taken over, so bitcoin cash was created. That's just one example among many.
How do you define a "post market economy"? Is that like a gift economy or like a "post-scarcity" Venus Project like thing?
Technology is creating means to have nonpoint source production of goods and services. 3D printing enables people to create any number of the parts and supplies they need from basic stock, and the manufactories being replaced range from stonework to living organs. This is presently available in models you can buy today for as little as $50, although that'll get you cheap plastic parts.
It's difficult to overestimate the level of disruption this will create in every field you can imagine, from Law Enforcement (weaponized drones) to Medicine (printing your own drugs and even organs in situ), but the concept at it's base replaces the capital investment model altogether--along with the social control mechanisms that support it, such as government.
With some few additions, such as mesh networks (to decentralize communications), and cryptocurrencies (as a temporary medium to replace the legacy capital system during transition) it is inevitable that continuing development of these extant technologies will make capital itself obsolete.
These aren't technologies that need to be invented. They exist now.
In 'The Diamond Age' Neal Stephenson postulated streams of atoms being delivered to people's personal printers by nanobots. In 'Transcendence' this network of nanodevices is networked and self aware.
The infrastructure concomitant to global and societal evolution takes time to create, and refinement and development of technology will continue to improve capabilities and reduce expense, until literally anything you want can be made to order at no cost.
Nothing stands in the way of this technically, except those who need power over people, which they will no longer possess when their money can't buy it.
There will eventually be no need to buy anything, because you can just make it. There will be no essential services you (and your neighbors) don't create yourselves.
There will be no necessary markets. There will be no need for money.
This is what I mean by the post market economy.
I enjoyed reading The Diamond Age and watched the Transcendence movie (though I hear the book is better, I still really enjoyed the movie). I get where you're coming from, and I don't think you're wrong just possibly premature. Time will always be a scarce resource. There will always be inequality because there will always be different ambitions and different levels of commitment regarding time spent working vs. time spent in leisure. I don't see that ever changing. Money is just a token on a shared ledger of understanding for who is providing value to others. At least, that's what sound money is supposed to be. Those who rail against money, I think, are really railing against the distortion of money and how separated it is from what humans actually value via government and central bank monopoly control.
Even in a 3D printed world, our expectations will change, as they always have. People believed cars, washing machines, dish washers, etc would create so much leisure that people wouldn't need to work anymore but instead we chose new things to work on. We're always creating. We're not a static species. We'll be working to build communities on Mars and beyond, if we survive long enough.
I don't see this ever being a reality within our lifetimes because that level of production and consumption would quickly destroy the planet we need to live on. You said "services" but then said create. Not everything we pay for is a physical thing that can be created or bought. Much of the economic activity in the world is service based and AI's are making great progress there, but are still a ways out.
I like the Star Trek dream of no money and no markets but every attempt at it on a large scale so far has lead to massive amounts of human suffering. On the small scale, I think we're starting to see sustainable communities live out what you're describing, and I think it's a beautiful thing we can all learn something from.