source:
https://forum.bitcoin.com/ama-ask-me-anything-f69/i-am-wences-casares-co-founder-ceo-of-xapo-ask-me-anything-t2025.html
Of all the ways in which Bitcoin could fail the one that worries me most, because I think it has the highest probability of all the bad things that could happen, is a price panic that drives the price to zero, or $15, from which it may be very hard for Bitcoin to recover the public's trust.
Right now most of the money that is invested in Bitcoin is money people can afford to loose and that makes it safe money. So when Bitcoin goes from $1,200 to $200 there is not a vicious cycle of people who need to sell, because they cannot afford to loose more money, that drives the price to zero.
It is hard to estimate how many people on bitcoins, but it may be somewhere between 13 and 15 million people right now. If Bitcoin is successful we will see hundreds of millions of people own Bitcoin and, eventually, billions. The only way we can get to billions of people owning Bitcoin is by the price going up by several orders of magnitude, let's say $ 1 million (but this is highly speculative and risky). So, if I am right, and Bitcoin has to go from $390 to $1,000,000 the best way for it to get there without crashing irreversibly is with as much volatility as possible.If bitcoin went up a couple percentage points every week and everybody began to think about it as a "sure" thing, investing money that was destined to pay for kids colleges or for retirement, that is a disaster waiting to happen price wise. Because when Bitcoin corrects those people have to sell because they cannot take more losses, potentially creating a vicious circle which is hard to reverse.
Ironically, we have to thank Bitcoin's volatility for people not investing money they cannot afford to loose. As long as the Bitcoin price remains highly volatile and perceived as risky, we are OK. Begin to worry when it is perceived as a sure thing that everybody should own a lot of.
I wholly agree when he says that hte greatest threat is some unrecoverable loss in value. But the longer we stay non-zero bound (e.g. sub 100) the greater legitimacy bitcoin possesses as an ecosystem that can recruit adoption.
Where I disagree with Wences is that we are not going to 1m unless there is some catalyst, volatility alone wont get us there. For us to become magnitudes of order higher than 300$, there must be a singularity whereby there is a massive and sudden rush of adoption. How we achieve that event is unknown, but the best bet is that there is something out there that is ready to become imported onto bitcoin's blockchain.