"The sharp bull markets including tech bubble of the [late] '90s, US stocks of 1920s, oil in early 2000s and even the famous South Sea Bubble do not even come close to the rise in bitcoin."
It came after the chief investment officer at Japan Post Bank last week said the current bitcoin craze was worse than the dotcom bubble in the late '90s.
According to Katsunori Sago, the fair value of bitcoin should be around US$100 ($146.99)
- nearly 99 per cent below its current level.
"During the information technology bubble, we saw a rally in dotcom company shares," he told Reuters.
"But at least at that time, there were people using Yahoo or [Japanese internet firm] Rakuten - people were using their services.
"But this time, I see quite a lot of people doing crypto-currency businesses in my circle of friends. But I hardly know anyone in person who is trading crypto-currencies and I haven't seen anyone using them in real life. So in that sense, it's worse than the IT bubble."
AMP Capital chief economist Shane Oliver described the figure of US$100 ($146.99) as "arbitrary", but agreed the current bitcoin boom was like the dotcom bubble.
"Every so often something like this comes along, every generation gets sucked in," he said.
"Often it's people who don't know a lot about investing. During the dotcom bubble, at the time the standard response to anyone expressing scepticism was they just didn't get it.
The dotcom shares inflated to excessive valuations, many had [price-earnings ratios] off to infinity but no earnings. This reminds me a lot of that."
Dr Oliver said as with all bubbles, there was "some core of truth behind it, some fundamental innovation".
"The key innovation here is the blockchain technology, which is a snazzy way of making a currency or transfer system without having a central authority," he said.
"There is a lot in it, but the trouble is it's just another means of payment or an alternative currency. That has value, but not US$8,000 ($11,759) worth. It generates no income. Then it's a question of why a currency should be worth so much. Currency is usually seen as a medium of exchange or a store of value, but not an investment.
"I think what's happened here is a lot of gullible people have concluded there is value in this, and I agree there is, but then they've extrapolated that to this as being the way of the future and saying therefore it's going to keep going up in value."
In September, JP Morgan boss Jamie Dimon weighed in, describing bitcoin as a "fraud" only fit for use by drug dealers, murderers and people living in places like North Korea.
Mr Dimon told a New York conference we would fire "in a second" anyone at the investment bank trading in bitcoin.
"For two reasons: it's against our rules, and they're stupid. And both are dangerous," he was reported in The Guardian as saying.
"The currency isn't going to work. You can't have a business where people can invent a currency out of thin air and think that people who are buying it are really smart.
"If you were in Venezuela or Ecuador or North Korea or a bunch of parts like that, or if you were a drug dealer, a murderer, stuff like that, you are better off doing it in bitcoin than US dollars. So there may be a market for that, but it would be a limited market."
Prominent American author and finance commentator Jim Rickards has also taken a dim view of bitcoin. "Bitcoin could go to $8000, $10,000, or $20,000," he tweeted recently. "It doesn't matter because it will end up at zero. Neanderthals had their day too."
Asked for his long-term outlook, Rickards argued the digital currency "may not be around in 20 months let alone 20 years".
"As for gold, it's an inert element in the periodic table; you can't destroy it if you try," he wrote.
Bitcoin's boosters, however, scoff at frequent "tulip" references and describe the likes of Mr Dimon as dinosaurs of the old-world financial system scared their jobs are obsolete.
"Guys like Dimon believe they own the system," wrote Jeffrey Tucker from the Foundation for Education Freedom.
"They are the great intermediaries. The masters of the monetary universe. No one gets in the system or out of the system without their knowledge and permission. So it has been for thousands of years.
"Bitcoin changes all that. Download a wallet, find a friend, and you are the owner of a currency that can buy anything in the world, from anywhere in the world. It's more than that: any individual can raise capital, without intermediaries. Without JP Morgan."
