Nobody can ban a cryptocurrency. You can not ban bad weather too. Ok,you can,but you can not expect that the ban will be effective. It would have been banned many years ago. I think you still do not understand what is the blockchain.
Predictions are just something pulled out of ass. It is just fun, like horoscopes, nothing that can be taken seriously. Yes bitcoin can be 500K or 0, or anything in between. Or over that. Ethereum can go to 300 and then to 30 or 3 or 0 if they make another mistake in code or the main preson of ETH is killed. Same for bitcoin. Price of ETH now goes up, because a lot was built on ETH and lot is expected. But yes, blockchain is the technology of future, just we do not know even roughly where it will have sense.
All cryptocurrencies are on fire. The smaller made even bigger progress than ETH. But I think you are doing another mistake. Cryptocurrency is not currency as money. Some, maybe just the one, yes. The other cryptocurrencies are more like a tokens. It can represent kind of a new class of share. Or something that we can not imagine. But not money. Cryptocurrencies are many assets, very much different put together. They have only thing in common - the blockchain.
Imagine that someone would talk about electric devices in 19th century. And that they are on fire. He can imagine electric car (right) or locomotive (right). He would talk about electric plane (wrong). Power plant (right). About getting electricity from flashes and storms (wrong) and from ocean waves (right but it will take one century). About electricity in medicine (directly just partially right). About artificial cities deep undergrund (wrong), electric toothbrush (right but not big business). But that is not everything! He would miss radio, tv, computers, electric dildos, online gambling and many other things with highest ROI completely, because it was beyond imagination and also some of those things were invented one after another.
So this is where we are. Blockchain is the gamechanger, the new multitrillion industry, that has valuation only 40 billion (was 5 billion 2 years ago, and 20 billion 2 months ago). And nobody knows what will be useful and when. Like one could feel it in 1990 with internet, 1970 with computers, 1960 with LSD, 1900 with radioactivity and so on. It will not only change economy. It will change whole society (for both better and worse). It is the direct connection of people without middlemen. But not everywhere. Only where it will have sense. Like technically we can built big intercotinental electric powered airplanes, but they do not make sense (yet). It will be the market, that has to prove, where the sense is.
So far market verified only one blockchain use and that is blockchain as almost-money. The other blochchains aspire for other uses, but we will yet see if it makes sense.
One example that will be crystal clear for everyone here: provably fair games. With blockchain and cryptography the casino players can see that the computer game is not rigged. Nice right? We all know the stories how players bitch that the games are rigged, so from now they will not. It is a big change... Oh wait. What if we just think it is a big change? What if casino players are just losers that actually like to have the excuse for their gambling habits. What if they dislike the fact they will lose the excuse and the game will lose the spirit with "provable fair" gaming. Or what if 99.9% of them do not give a ****, so it is better to run the casino game on stupid cheap RNG generator and one database? Only time and market will tell, but many cryptoinvestors think it is a good bet.
And that is not everything. Market also has to decide what is the optimal security (=costs) of the particular blockchains. Like bitcoin is very secure, some say too much over the necessity. ETH is not so much secure and soon they will make another change, that will make it prbably even less secure (but less costly).
Decades of trial and error and coming. So yes, predictions are nothing serious. In 1900 many people could predict man on Moon in 1945, 1968, 2017 or never. Looking backwards - probably any estimation could have been right.
My advice: buy the cryptos. Buy that much you can lose or you want to risk. It even does not have to be a lot. But it changes a lot for your perspective and that perspective will be maybe more important than the valuable bag of bitcoins. After you are hooked, you will be able to do other more informed decisions. It is like with SEO for example. You can read about it a lot, but doing it changes things and only then one truly learns.
If you talk to God, you are praying; If God talks to you, you have schizophrenia.