Traditional banks have lots restrictions _when_ you want to withdraw cash. Try moving more than $10000 between borders of countries that are not friendly with eachother, and you'll find those restrictions. You can travel with a hundred million dollars of BTC in your head (or a hardware wallet) and meet up random people if you want to buy something with it.

As an example Michael Saylor could change aegentin peso to USD in an argentin bank ($1M), but the surprise came when he wanted to move it to US.