His pathetic excuse is typical of authoritarians throughout history (although he is probably more likely a useful idiot that an out and out fascist/communist), he wants to prevent a sick thing, in this case child pornography sales although he could equally have chosen the prevention of terrorism or the promotion of equality as his excuse.
However the effect of his bill would be to ban anonymous pre-pay credit cards in general for everyone, not just those that want to download pay per view images of child abuse. Because he would fine the providers of such cards if they were used to purchase certain things it would become impossible to provide such a service.
Proponents of liberty have long recognised the importance of having anonymous payment methods.
Imagine that a crypto authoritarian government, in the modern age, decided to get rid of cash.
They could sell the idea to lefties by saying that it paved the way for progressive VAT and they could sell it to the cowardly by saying that it prevented terrorism (because you can just stop the terrorists cards whereas you can't stop their cash) and they could talk about how it would ease cashflow in the economy (because there would be less money frozen in the form of bits of paper in people's wallets). It would also, they might argue, make it harder to pay for prostitutes and child pornography and illegal drugs and guns and stuff from sex shops etc.
They could then even implant the credit cards under our skin to make sure that no-one else could use them.
Clearly if any government tried to do any of this we would see this for what it was, a grave attack on liberty.
However with more and more of the economy moving onto the internet it is important that the ability to continue to trade anonymously is protected.
These credit cards are the online equivalent of cash!
So this is no different to the horrific dystopia described.
The BBC article: http://www.bbc.co.uk/news/uk-politics-10709128
ps I've never used one of these cards. I've never had cause to, but my liberty is protected by their existence and the fact that I cold use one if I wanted to and, as more and more of the economy moves onto the web I may well want to use such a card.