Is it safe to keep all of my assets in Bitcoins? And how Department for Combating Economic Crimes, can affect my account? What permissions they need , to freeze all my money ?
well as far as 'freezing' your funds no government can take stop you from moving your BTC. there is no central 'bank' that can make address 1MogRiTHpQZ7bkpq49cSVWADrTt7Jrghp suddenly not work. Now if they find the computer that has that address and my wallet password they can move BTC out. But you can make a paper wallet that has private key and hide that. unless they find that the BTC is safe.
But as several others have said here the value of that BTC can change a lot. you may buy 925BTC today and 5 years from now you will still have 925 BTC but whether you can sell it 600, 6 000, or 6 000 000 no one knows. you can say the same about a kilo of gold but can be more sure it will be closer to the same amount that you started with.
Ross Ulbricht when arrested gave up some keys but he could still have a hidden paper wallet somewhere.