Bitcoin, like any so-called crypto currency, is the old like world scheme of Ponzi. Only in the new high-tech pack.
Want an example? You are welcome:
1. Assume that all people in the world convert half of their savings from ordinary national currencies to crypto-currencies. What does it mean? This means that the producers of crypto-currency, received half of the world's volume of national currencies - half of the total world currency bascet.
2. After a while, the fictitious value of investments in crypto-currencies increased 4-fold (as we see in the case of Bitcoin and the mass of other crypto-currencies). What does it mean? This means that now, every person in the world, reasonably expects to receive in exchange for his crypto currency (as a return on his genius) in 4 times more volume of the national currency.
3. Let's assume that all these people, at the same time, decide to fixed their investment profit-to exchange their crypto-currencies that went up four times, (if they take profit in the form ordinary national currencies).
All of them expect to receive now 4 times more national currency than they used to, they spent on buying crypto-currencies.
QUESTION: Where does this whole currency come from? From producers or producers of crypto-currency? But they simply do not have such volumes of ordinary currency, and never were. Because, previously selling the Crypto currency, in exchange for the usual currency, the organizers and the receivers only received the initial value of the crypto currency in the usual currency. Which was at the time of the transaction only - 1/4 of the amount of currency, which is now payable to all owners of the crypto currency.
CONCLUSION: Bitcoin, like any so-called crypto currency, is the old world scheme of Ponzi. Where each participant can receive a gain of the investments only one way - due to those new participants who have entered this pyramid later.

If half the world is using cryptocurrency, is there any possibility that people still need to convert their cryptocurrency to fiat before they can use it?