What do you legally “own” with Bitcoin? A short introduction to krypto-property

One section of this article is fairly accurate - a custodial holder of an asset (e.g. a bitcoin exchange) doesn't "own" the asset.

They have a contractual liability to the actual owner completely irrespective of any on-chain activity. It's not really even a "Bitcoin". The customer doesn't care whether they get the same Bitcoin back - they just want A Bitcoin and a legal agreement was specifically entered in to for safekeeping.

Outside of that, the majority of the article seems like someone external to a system trying to muscle their way in and exert authority over the participants in that system.

There already exists a mechanism to determine ownership in Bitcoin (e.g. "physical" Bitcoin, the cryptographic system).

A UTXO requires a puzzle to be solved in order for it to be released. This puzzle may or may not require the input of multiple parties.

The participants in that system accept this basis.

A court _cannot_ force a Bitcoin holder to give up their key except in specific cases with naive/bad key management. It is actually impossible to seize. Cooperation is required.

People can be locked in boxes, but a sole owner of a private key is the owner a priori because no legal title is required in order for them to maintain sole use.

It's literally the entire point of the system - if you revert to Men With Guns as the dispute mechanism then you may as well scrap the whole thing and use traditional banking.

bitcoins introduce an artificial scarcity with its mining algorithm (there's only so much bitcoins out there)

Is bitcoin still a thing?

Sure, courts cannot freely move Bitcoin from address A to B, but that's not really relevant. The relevant part of ownership in this context is whether moving Bitcoin from address A to B was legal, i.e. did you have the ("ownership") right to act with that Bitcoin? And the answer sometimes may be "no", even if you had the key (which you obviously did, if you made the transaction); the question "whether that transaction was fraudulent, did you commit a crime by making it" depends on who legally owned these Bitcoin, not on who knew the keys.

And in many cases courts can move Bitcoin, and have done so - hardware can be seized, people forced to reveal passwords, and Bitcoin transactions executed. For example, see the multiple auctions of seized Bitcoin by U.S. Marshals Service. They can't be guaranteed to succeed, but that's nothing new (it's not like stolen goods or cash always get recovered), and they certainly can try.

If someone steals something edible and eats it, courts also can't return that thing back to the owner, it doesn't mean that edible things are owned by whoever eats them. In both such cases, the courts can order (and, as much as possible, force) the culprit to compensate the rightful owner - but it matters who the rightful owner (in the opinion of the court) is, so it is meaningful to debate who owned it.

The system doesn't really considers ownership. All participants could, individually but all, simply follow the rule (R):

"this 'address' (x) actually won't spend anything, ever".

Since participants are actually free to move into that rule, that x "owner" (person X) never owned btc.

Person X can't say he was "disowned"/"robbed"/"stolen". Each participants is free to do whatever they want with their computers (they could, individually, even shut it down completely - so everyone could actually shut it down at the same time and no one ever come back).

If Person X is to "actually own" bitcoins, then he (or someone) owns every participants computers, so this owner could state (or enforce) the rule "you shall not move into rule R" (because you would be disowning person X without X's permission, which would be aggression and be unjust).

So knowing a private key "just happens" to interact with each blockchain on the participants computers. They "just happen" to not ignore that information, and interact to it in a certain way. We, in practice, consider the filters the participants decides to apply as having the effect of simulating ownership. But Bitcoins are not actually owned by anyone.