Saying blackrock, for example, “owns” their underlying Bitcoin ETF holdings is no different than saying Coinbase “owns” it since they actually hold custody.

They are required by law to hold the asset backing their ETF and so you could say it even “belongs” to the investors. All of these are ultimately incorrect.

Who really “owns” it is the US government as they could pass legislation to seize it at any moment. If they can change the constitution to legalize income tax, surrender their sole constitutional authority too coin currency to their banking donors and establish the Fed, issue an executive order to seize gold from private citizens, etc. then they can clearly pass legislation to seize the Bitcoin holdings in the event of a dollar collapse or “hyper-bitcoinization”.

In fact, it would be incredibly foolish of anyone to assume they wouldn’t.