> If your key is secret, your coins cannot be taken away from you.
Governments have a legal monopoly on the use of force, and they have the means to employ it. If you can access your bitcoin, and a government can access you, that government can access your bitcoin.
> You don't have that option with digital fiat, even if you wanted to.
Yes, you could, you just need to acquire the digital fiat anonymously through one of many methods. Then burn all record of it and watch your money disappear the same way as taking it to the grave, just no death required. Or go ahead and die if you must, but you’ll still not prove that Bitcoin is any different or any less “takeable”.
Technically true! However, if you want to be dead and have nothing to pass on to your heirs, there are many other options which are easier and more fun.
You could possibly get around this by sharing the keys without sharing that they are keys like teaching your young children to sing a song or some other activity that matches the mnemonic phrase but can be passed off as a weird family ritual or something and only later revealing the secret to trusted beneficiaries.
Governments have a legal monopoly on the use of force, and they have the means to employ it. If you can access your bitcoin, and a government can access you, that government can access your bitcoin.
https://xkcd.com/538/