alt Hacker NewsThe government could also tax you an extra $5000 out of nowhere by pushing a law through. That levy happened to go for bank accounts but the general concept isn't tied to whether your money is stored personally.
Freezes are a big problem but they don't get to keep it. The delay is the problem, not a transfer of ownership.
Nonetheless, there's a fundamental legal difference between ownership (e.g. of the notes and coins in your pocket) and a chose in action (the right to sue the bank for the money which you don't own).
If you own something and someone withholds it from you, in the general case that's theft. Because theft is a criminal offence, people generally won't risk doing it. With a chose in action, you have to sue in a civil court for damages. In the meantime, the bank might go bust, you might lose your case, you may give up without even going to court because the amount they've kept isn't worth the time and legal costs of recovery.
You've probably heard the phrase "possession is 9/10ths of the law". If the government introduces a no-warning one-time $5000 levy, they still have to recover the money from you. The effort of doing so is on them and they have the burden of proof. Maybe they will, maybe they won't. Maybe you'll decide to leave the country before the legal process concludes. These are some of the advantages of ownership.
When the money is in the bank, the bank and the government can simply agree (without a court's involvement) that you owe the $5000 and there is nothing you can do other than try to sue the bank (and likely lose) because you never owned the money in the first place. The burden of proof shifts to you and it's unlikely you'll ever see that money again.