All ownership (digital or not) is nothing but a social contract. The cryptocurrency (or normal currency) exists because enough people agree to recognise it.
You can buy and own a domain name. If trust in DNS is violated, we'll have much bigger problems.
Owning a token means you can perform certain actions on a distributed system. No social contract needed. You own the token by owning a secret key which gives you the power to move it.
It's like owning a key to a door. It gives you the power to lock and unlock the door. No social contract needed.
You can not own a domain. You can only pay a registrar to have them talk to a registry. You then are at the mercy of both. Use the HN search tool to read an endless amount of horror stories of people who lost domains and sometimes decades of work because of this.
The distributed network exists because we collectively agree to host the nodes, and because we put trust in that network, and in its supply chain (application, OS, hardware, electricity, clay, etc). Ownership is built on that trust - exactly the same as your ownership of a domain name is built on the trust in the registrar, ICANN, root name servers, and so on.
Suppose a hypothetical scenario, where a malicious actor sneaks in a bug into the node's code, that causes the requests signed by your key to be rejected, and the code gets deployed to the majority of the network. Your key/token becomes effectively worthless.
Suppose a (much less hypothetical) scenario, where a state decides to outlaw the technology, which puts node operators/users at a legal risk, disincentivizing the use of the network locally, and diminishing its value globally. You still "own" the token, but it's that much less useful.
There are different considerations, trade-offs, threat models, failure modes, horror stories, but nothing about ownership in a decentralised network is _fundamentally_ different - it's still built on trust.
A door-and-lock is a single-agent system and therefore isn't a good analogy. Money always needs social consensus. In a blockchain, you're relying on others agreeing on a certain history. That society can decide to disagree with you and consider a different history as truth. It has happened multiple times on Ethereum and Bitcoin both.
When you own property in real life the record of ownership is maintained by the city/state/country.
There's no reason why the ownership in digital space has to be on a decentralized blockchain, you can also record it centrally (as shown by trusted entities like VISA etc).
Why is that a problem? I "possess" nothing in digital space but get much value from it and I posses various things in meat-space that I also get value from.
Moreover, I can spend my conventional money in digital space and get further use from. A "digital possess" seems a thing that doesn't improve the world in a good way.
Crypto makes so many things so much more efficient
Like what? I can currently pay for any legal physical or virtual good I can think of using a conventional credit card. Crypto might or might help privacy and might allow you to buy illegal things more easily. It's a hedge against inflation but a number of things have that quality.
The use of crypto seem inherently confined to keeping the state from doing things to people's money. States can be terrible but since crypto doesn't stop state from doing things to people's physical person, it's most often a protection of the rich from the state, which isn't something I'm particularly in favor of either.
I think there are a lot of "W3 revisionists" or people who are otherwise maybe too young to remember the mid-90s but from what I remember there were plenty of people who saw the potential of the internet. Twelve years after the web was laid out at CERN we had Google not to mention AOL, Ebay, Craigslist, etc..
I've been hearing the same story on crypto since 2011/2012 and it's become no more useful to the average person. The only thing that's changed is more people who know nothing about technology are raving about how its going to change the world so I should buy Bitcoin.
So if a country makes the possession of cryptocurrencies illegal, it makes their people digitally possessionless.
This would cut them off from the next version of the web. Similar to how North Korea cuts of their people from the current web.
So far it seems no country that cuts of their people from the internet has been able to flourish.