Bitcoin is the first store of value that you can send anonymously, digitally, and without involving central authorities. None of your other examples are as useful.
Sure, that's correct but it's not really the whole picture. Cash in an envolope works too. And it's quite hard to acquire Bitcoins anonymously unless you buy it for cash from someone local.
But Bitcoin is unique in its cheap international transactions, while still being somewhat pseudonymous, I'll give you that. I just don't see the potential in anonymous tax-avoidance as something groundbreaking compared to its other virtues.