Part of me (the cynical part) thinks that people like Rickards and Shiff are just playing dumb. I would if I were them, there are several reasons to do so (not least that Schiff runs a business based around gold as money/value store).
Bitcoin is entirely unproven. It is immature. It has barely been in the public eye for long enough to be seriously studied and reviewed.
Hmmm, the sort of people I would take seriously have already put Bitcoin through a great deal of study and provenance, ever had your wallet stolen? This is just like those that say things like "one day, Bitcoin will be a viable method for transferring money". When what they're really saying is "one day, I'll stop putting it off and use the damn thing". I've personally been using bitcoin for all of the purposes that it supposedly can't be considered for yet for several years now.
The software works. The math works. What remains is it being money wherever you might expect it to be money, and for less people looking at you funny when you want to give it to them for something they value.
Not so many people will refuse gold as payment, world wide.
Money is more than working software, money is in the minds of people, it is memory.
I agree with you that the review of Bitcoin is good enough for me, and I prefer bitcoin over any other payment type. We are not most people, yet.
Even if, and after,
BTC gains popular acceptance, it will take some history to pass by, decades, before it will be deemed a success. The world is perverse. The best things are not always the ones that win or even survive.
I will never give up on Bitcoin. I made a promise to someone that I refuse to let down. I will keep that promise come what may, but I know better than to take success for granted. There is a lot of hard work between here and there, and much stacked against us.