That's what multi-signature escrow is for. You deposit money into an account and you have one key. The vendor has one key and a third key is given to an arbitrator and at least two keys must sign the transaction in order for it to be completed. If the vendor sends you your product and you are happy with it, you sign the transaction and the vendor signs the transaction and the vendor gets the money. If the vendor does not send you what you ordered, you talk to the arbitrator and the arbitrator listens to your case and the vendor's case and makes a decision.

I feel it's speculative something like electricity was speculative in the early days of electricity when people were doing it wrong and burning down their houses and people laughed at electricity like who would ever want that and now we can't really live without it. I will agree, cash is a bearer asset and untraceable and therefore is very good. The only real problem with cash is that it's based on the monetary policy of the governmyth that issues it. They make bad decisions and you suffer for it.

Edit: That and it's kind of hard to stuff cash bills into my computer and get them to come out on the other side halfway across the world.