General comment:
In my opinion it is very likely that crypto currencies will be used worldwide. I don't know when and I don't know which. I am just pretty sure, that crypto currencies in general will be used. I also think it is very likely, that the world will not trust on one single technology, but use more than 1 good crypto platform/currency, because redundance is needed for such an important system as our financial system. Also: We don't know yet which features will be needed/important in the next years and that's another reason why it is very likely that not only 1 crypto currency will "survive". So everybody who is truly interested in blockchain technology should stop attacking any other crypt platform/currency and just focus on the development and the different features. This is no "i win you lose" situation. Good technology will survive (of course like always a little bit of luck is also needed, we have enough examples for this in the past).
I took this stance, but upon a bit more thought, my view is:
Governments will take Crypto technology and build their own within the current financial system (
This is already happening, and was predictable.). With this in mind, I also think it's not unreasonable to assume we just don't end up with a new elaborate scam just as what FIAT had become. (Fractional reserve banking, etc)
Governments hate Bitcoin, because they can't control it. They hate Gold/Silver - they can't print it. Solution: Build their own crypto, one that they alone can control, exploit and manipulate. If successful, this will drive down the price of Bitcoin/Alts considerably (And most certainly kill off most Alts that have not seen reasonable adoption)
Existing crypto's like bitcoin will always have a purpose -- but one that serves those who wish to do less then legal trading. Black market trade is and likely will always be the only way alt currencies will survive and maintain some semblance of purpose and value. The popularity of "anonymous" alt's is solid proof of this. Crypto was a rebellion both financially and in terms of trading, after all, so makes perfect sense.
In other words, crypto will not see the widespread adoption as what people think, because governments will already be utilizing similar technology -- the general population will go about their day to day lives with no dramatic or jarring change, it will be seamless.
Bitcoin (And altcoins - at least those that don't die) will remain a a slight novelty with benefits, and in the event that things do go south with Government issued money/government issued crypto, people will flock back to Bitcoin and alts.
This is my opinion on what the future of crypto will be like.
This bodes both good and bad for Crypto - firstly, it shows government acknowledgement of the legitimacy of Crypto and this in turn drives investor confidence. At the same time, crypto was invented as a means to undermine (and challenge) the current financial system which was, in a nutshell, exploiting people and impoverishing them. This was by design. Thus it's no wonder the only successful coins are ones that embrance anonymity and black market trading.