While a) and b) are correct of course, but valid for normal currencies, too, I believe it creates real value by providing a worldwide currency which is difficult to control by governments and which circumvents the existing banking system, while avoiding any centralisation like with Paypal. For liberal democracies, the value add of this may not be as strong as for authoritarian states, but that will change as debt levels rise. You will be surprised what happens when Italians, Brazilians or even US citizens start using bitcoin to get around currency controls.

The competition of other cryptocurriencies with improved technology is not a big issue – yes, there is an infinite number of such cryptocurrencies which exist or could be born in the future, but those are even now easily convertible with bitcoin, so in a sense a part of the bitcoin universe. In other words, if you decide to buy some bitcoins, you would be well advised to put part of the money into ETH, LTC, ETC etc., similar like investors would usually mix their share portfolio or combine gold and silver.

If you observe bitcoin over a longer period, maybe 5 years, you will see that there is a pattern of slow increase, followed by a mini-bubble of fast increase with a breaking point when the mini-bubble bursts, then some dead cat bounces, a stable or slowly decreasing phase changing into slow increase again. For me, this makes sure the classic bubble investors, large and small ones, are deterred regularly while the bitcoin technology and ecosystem developers and practical users of bitcoin grow in numbers and develop more usage possibilities for bitcoin.

The diversified ecosystem makes the bitcoin universe more resilient than typical bubble objects. And the technology behind it, blockchain, has the potential to change how the world is working, starting with banking but continuing to property registers, law and many other areas, including, finally, government. I am no technology optimist at all but I can see the potentials here.