Here is the most authoritative answer any one can give: No One knows!
Whether you think it will go bust, stay flat, or skyrocket it's all conjecture. No one really knows.
What we do know is blockchain and crypto currencies are here to stay (at least until the lights go out
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BTC would not be the first new technology to blaze the trail and then get replaced by a better version with refinements to the process. While we can thank it for bringing cryptos to the awareness of the general public. there are some glaring problems with using Bitcoin as a currency.
1. Most people don't want to gamble their everyday checking account funds on something as volatile as BitCoin. It's success could well become the reason for it's demise (which futures might play a role in).
2. The scarcity factor. While that has certainly played a role in it's rise, a currency for general circulation needs more liquidity.
I would keep your eyes open for a crypto that brings the following factors together.
1, Greater quantity/Liquidity: If your going to use it to buy groceries, gas, bridge tolls, etc., you need easy access to adequate quantities.
2. More price stability:
Do you really want a currency whose value can fall by half between the time you deposit a paycheck and the time you pay your rent? We've seen that with fiat currencies. It's called hyperinflation.
3. Some investment quality (inflation insurance):
Imagine a crypto whose price was pegged to something in the real world. It could be gold or silver (or any other commodity), but it could also be pegged to the dollar adjusted for inflation, so if inflation is 6% your money gains 6% against the dollar as you hold it. With a peg like that you would have an incentive to get out of dollars and into the crypto as fast as possible, but without a scarcity factor it would not drive the price up or become hard to get. This structure would give average people the ability to hold their ground against inflation. If the dollar ever collapses, your protected.
4. Broad commercial and acceptance with banking support:
Imagine a crypto debit Visa card that allowed you to hold a crypto currency, but pay in your choice of dollars or crypto. So you buy some thing on amazon and they take payment in crypto, so you select crypto, but then you buy a loaf of bread and they don't take crypto so you slide your card and they get paid in dollars (your bank converts your crytpo into dollars at the time of sale and pays the store in dollars.
One of the things that has made cryptos attractive - the speculative investment potential - also makes them less attractive as a currency, so as this area matures, I'd look for a crypto with some or all of the previous characteristics to become a common currency.