It is a fake fiat second currency created by the PCC, which allows the Cuban politicians of the governing party to become extremely wealthy, just like the corrupt capitalist politicians of Miami.
You do not get good value for your dollars when the Cuban communist government forces you to change your dollars for CUC's,
What you are carrying in your pocket is basically a Cuban turd.
Homo Sapient is by nature a very corrupt individual. The communists are not any different.
It is my wild and unscientific guesstimate that if the true Cuban National Currency, the peso was allowed to trade in an open and true free market, you would get 100-200 Cuban Pesos for one dollar. Maybe even more. Since everything in Cuba is controlled by the PCC, there is no open or free market in the island.