I'll have to fix some info.

Currently there are two legal exchange rate systems:

• Sistema de Divisas Protegido - Dipro (Protected Foreign Currencies [Allocating] System). This rate is set by the Government and it is used to import basic goods (food, medicines, etc.) and to pay pensioners who live abroad.
  Current rate: 9.9750 VEF/USD (bid) 10.0000 VEF/USD (ask)

• Sistema de Divisas Complementario - Dico (Supplementary Foreign Currencies [Allocating] System). This rate is theoretically set by the market, however, according to the economist Luis Oliveros there is no evidence of such, hence it is likely to be managed as well. It replaced the Simadi in April and expectations since its announcement have curbed the black market value of the dollar.
  Current rate: 415.5879 VEF/USD (bid) 416.6295 VEF/USD (ask)
  

According to the Venezuelan Central Bank latest data the first one assigns 92.17% of the foreign currency and the second one the remainder.

As you can see there is already a terrible distortion in the licit market which is unsustainable since people who can get dollars at the most overvalued rate (mostly the enchufados, those with ties to officials) are able to sell them for a greater quantity of bolivars which will then be used to get more dollars and thus perpetuate a vicious cycle. Anyway, there is no hard currency left, not even to pay key contractors of PDVSA, to import food or medicines or to print money (Venezuela doesn't produce anything). The last bastion of the private sector, the brewing and food company Empresas Polar had to halt most of its production due to lack of dollars needed to pay for the inputs. The Government blames the "bourgeoisie" for the economic paralysis and it announced production plants will be seized.

With regard to credit/debit cards, there is no such thing as VISA or Mastercard in Venezuela as the national services are disconnected from the rest of the world and sums in foreign currency (cupos, quotas) destined to credit/debit cards are to be approved as well. If and when people miraculously manage to be granted foreign currency to be used abroad their credit/debit cards won't work overseas because of the debts accumulated by the Venezuelan banks with the electronic payment service providers.

My view about the use of Bitcoin in Venezuela based on SurBitcoin is that it is used mainly for remittances, in other words by Venezuelans living abroad who send money to their families also considering that 3/4 of the population are materially deprived and that the rich can always find their ways to expatriate their wealth directly in dollars. If affluent Venezuelans were interested in Bitcoin its local market wouldn't be so minuscule and skewed to the sell side.

As a final thought Bitcoin to function needs users who can satisfy their primary needs, electricity, computers, the Internet, knowledge. It can't be used in situations of distress due to the impossibility of fulfilling the minimum operational requirements.