Probably because lawyers are old-fashioned and there's less case law on the CPA , if indeed, they know it exists ! We know where we are with remoteness and snails allegedly in ginger beer bottles. I say ' allegedly' becuse everyone's favourite case (ineffective flu and cold remedies come next) only went as high as it did, the House of Lords, on the point of law. According to Lord Justice Megarry, when the case was finally tried at first instance, the judge found that the presence of the snail was not proved by the lady. Not sure whether you get any bonus marks for that recondite knowledge. She was the kind of client that lawyers want to breed from. She brought the case as a pauper, but I hope she tried to appeal the finding of fact, difficult though that would be.
Why do you think one is easier than the other? It may be that the question is only to show that you know of alternatives, unless the CPA says " the common law rule of .... is hereby abolished". The remoteness test seems equally applicable to both, giving rise to an action, in the instant case