Liquidity may be viewed as conversion to desired currency within an hour, a day, a month or a year.
Is bitcoin as liquid as precious metals, paintings, houses, currency?
What of these "evade capital controls?"
How about Internet based assets?
Bank accounts, stocks, etc? The capital controls on these are based on the physical location of the entity acting as custodian.
The third party intermediary.
Cut him out.
A bit more. Here's a real simple example of "capital controls."
Country X has an "official exchange rate" of 5 money-units for 1 USD. But the street price everywhere is 8 money units for 1 USD. And everyone uses the street price. But merchants doing business with MC/VISA are forced to exchange at the official rates.
What rate does BTC transfer at? You figure it.