real estate, gold, and land. BTC has to be converted to real money to be spent in any meaningful way.. sure you can even find instances where a house can be purchased with BTC but what do you do about the day to day like putting food in your mouth and clothes on your back. You are gonna need fiat currency.
BTC is far from seizure proof. If you're sloppy with our seed phrase it wont be yours for long. Even if you are good with your seed phrase I'm sure a hammer and 15 minutes is all it will take to have a BTC holder screaming their seed phrase from the top of their lungs.
BTC is not the safest asset in the universe but there is little point arguing about this since those that think this will never come around to any other view than their own. It's more of a cult than a investment sorry if this is harsh.
Cryptocurrency may play a role in the future or it may not but it's certainly far from the safest asset in the universe. If the government wants you they are gonna get you(especially if you are from a western first world country)
USA gives out prison terms the length of football fields in years lol. Imagine this scenario US gov says you owe $XXX,XXX in back tax you say no i dont so they indict you on tax fraud charges you proceed to go ah ha I will never pay my money is in BTC. The prosecutor gives you a deal of give up your seed phrase and its 15 months in federal prison or you can not and get 25 years at trial. Which are you gonna do? The government didn't get your precious bitcoin but they got rid of their problem either way by locking you up for two and a half decades. You opsec is probably also not as good as you think so 4 months into that 25 year sentence they find where you had stored your seed phrase anyways