I think they are wrong in this case.

The guy doesn't stop talking about gold, and nobody says bitcoins are going to compete directly with gold or even other fiat money. Bitcoin will be successful ONLY just by taking away a part of paypal's and Visa markets. Those are their competitors and only with that its future is guaranteed as an exchange medium for some type of transactions. That might help stabilizing its price and allowing it use as the "digital poor's man value keeper".

BUT...

Taxes are NOT going to disappear and they are going to be paid in fiat currencies. No question. So fiat money will keep on being king over gold and bitcoins. I don't think bitcoin will ever be the unit of count in the near future, the dolar or some other fiat will be doing that.

People will be using gold the way they were using it (as an insurance) before bitcoin, maybe a little bit less, and way less than most austrians say we should. And there are reasons for that...

Today gold is rare and strange to most people, this builds some extra barriers to its use on top of the ones the governments/States created:
How do I recognize gold? I am not used to handle it.
How do I know my gold is pure 24 carat and not some yellow jewellery type 18?
How do I hoard it? shall I keep it hidden at home?
Most people (in "stable" countries) is not used to that with fiat money and with gold is even worse, even small quantities are very valuable and too easy to steal.
Shall I rent a bank security box? how much is that a month? how long till they get to keep all my gold?
OR Should I invest in companies or gold ETFs instead?... Warren Buffet will tell you YES!, even if they are not gold related, companies produce stuff and choosing the right ones will grow wealth (for you and everyone else), while gold just tries to keep old wealth from fading, "it doesn't do anything".
...
All those are REAL barriers of entrance to most people using gold instead of fiat money.

Due to that and the forced uses of fiat money you end up in a situation so that you cannot use gold to buy goods or services, neither in physical shops neither online.

Gold usefulness TODAY is not that great.

And even worse, even if you could use gold on shops, with current prices it's too valuable to be useful. Will you buy bread with a coin the size of a microchip? you'll need tweezers and very good aim!
Even with silver that is starting to be difficult.

AND gold CAN'T, by definition, be used online directly. You will most likely need to use gold-tickets or promises in paper or in digital form while the gold is deposited somewhere that it will not move around too often (it would be too expensive). That is you need to trust a company/bank, pay them a rent for the gold monthly, etc.

Bitcoin, on the other hand, has obvious advantages over fiat money and is more practical for many of todays uses that gold. Its strengths shine most on online trade and the ones to be worried are, as I said, Visa, Paypal and other current fiat money based online payment services.

Is bitcoin a bubble?
Well I can tell you what I believe its going to happen.
The current price, "bubble" or not, can't keep on going up like this. Sooner than later it will collapse violently, there is no question of that.

The real question is, how deep will it collapse? will it drop to zero?
I don't think so, whatever naysayers say, bitcoin solves real problems and it is useful per se, there will be always people behind it for some types of transactions.
I bet it won't go even below last peak price on 2011, or it won't stay so low for too long.
Yes, many people will get nervous and lose lots of money and flee to never come back. But many other will stay, cause bitcoin is useful.

Bitcoin current volatility is for sure not a good thing.

But the only thing that I think could kill-off bitcoin for good is an alternative cryptocurrency with better properties like, for instance, having decentralized instant payments confirmed in seconds, having a way to represent personal debts and webs of trusts and move them around, etc.