Like asking "is crapping a legitimate form of excretion?". What if the government says no? 
Well said, sir!
I think the great majority of people participating in that debate know nothing about bitcoin...
It's horrifying, but I don't think the implications are clear enough to the people who would even entertain a debate with that sort of question as the talking point: if you're having to ask whether or not a grassroots technical innovation is legitimate or not, you're basically saying you've already accepted a form of dictatorial government. The cryptocurrency toothpaste is not going back in the tube. The only "solution" is to eradicate all knowledge of it, and that's going to take some
Theres two contexts in which the title applies. Simpleton approach where your essentially asking wether we can freely trade the currency with one another analgous of other medians of exchange without the swift hand intervening.
The other context in which the title applies is the technical discussion of bitcoin providing a payment exchange mechanism that exists within its own ecosystem and that if its a viable form medium of exchange one that does not lose trust as a payment gateway because of its evolutionary origins. This has been proven to you and I but the avg joe is more concerned about the first context rather then if it is self sustainable or not.
Thats what I see when i read the title anyway.
