If we are talking about the purpose of Bitcoin, we should remember the context of its inception and the message encrypted in the genesis block:
"The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
This was probably intended to comment on the instability caused by fractional-reserve banking and to provide people with another option: peer-to-peer cash.
This is in fact extremely ironic. The banking crisis of 2007-2008 was NOT caused by any failure of the fiat currency system. It was caused by reckless speculation of financial institutions on "virtual assets" ... not any quirks in the issuing of fiat money, as can be seen by the relative price stability of most fiat currency in that period.
Jajajaja ... it's totally ironic. I think it provides people with another option. Andreas Antonopolis told a story in an interview about how he convinced his mother to put all of her money into Bitcoin in 2011. She finally did. Shortly after, the government took 20% from everyone's bank accounts. There is nothing wrong with fiat currencies, except politics, and that's also true with Bitcoin.
Sure, it is another option. That said, when government wants to take assets from people, they will always find a way, especially when the assets become "publicly accepted" (and hence also "declared").
But there's a difference between "freedom money" (of which I'm fond), and "sound money doctrine" (finite set of assets). Nothing stops freedom money from having an issuing mechanism that more or less regulates its value to a constant, and hence can become a much better unit of account than an inelastic amount of assets which will always turn into speculative items, because of their volatility (and especially, if "growing", by their greater-fool potential).
In as much as bitcoin was a great idea to have a decentralized monetary token, its economic policy is very naive and bound to failure (as an ideal monetary asset), especially because it has no elasticity.
Do you think maybe it was to mimic gold, as some have suggested? Perhaps it was to say "DON'T PRINT MONEY TO BAIL OUT BANKS!" We'll never know [hopefully] and that's the fun part. Probably some of both.
But gold never was a great money, and gold is special, because of its historical ground. Rare stuff just becomes speculative, and when it is speculative, it has not stable value, and when it has no stable value, it is not a good unit of account, and when it is not a good unit of account, it is not a fluid currency.
Also, gold "always existed" in a certain way, and the only thing that new gold sources did, was a "gold rush" which was always an economic disaster, from the demise of the native American civilisations to the disasters elsewhere ; but gold never faced the problem of extremely severe seigniorage, making huge fortunes of a few.
It will be interesting to see where it goes. It has a lot of benefits by being the first, but other currencies are able to adapt. DASH has seen the Bitcoin scaling debate and built it into their Masternode. They also have 100 DASH limit to vote. ETH is exploring proof of stake, which is a flaw with BTC; people can say all they want without having a dime invested and it takes time to distinguish on these sites.
I don't think Bitcoin will go away. I think it's great, but I am diversifying my portfolio (along with many others) and am mostly interested in LiteCoin and DASH. Having said that, I think any cryptocurrency that has a public blockchain can be legitimate and competes with BTC. If it's an internal blockchain, then, it probably has less value. I'm thinking Ripple.
My take on it is that bitcoin will stay, of course. But I think bitcoin has so many flaws, is based upon so many misconceptions, that it will never be what it was said it was going to be ; and bitcoin has been withholding serious crypto competition until recently, by its de facto monopoly of the market.
That said, my idea is that most of crypto, as of this day, is heavily speculative, and that this will only get worse, not better, because almost no token has self-regulating systems, and if they are, nobody is interested in it. Bitcoin has killed the dream of free money by being a get-amazingly-rich-quickly scheme like rarely has been seen before, and by having many imitators of that same scheme. DASH, for instance, even amplified the deflationary spiral with its master node scheme.
It is very easy to make a speculation-capped crypto asset, that will never fall into a deflationary spiral, but nobody would use it, because, exactly, the get-rich-quickly dream would not be included, and all the deflationary bullshit of bitcoin's monetary theory would be baffled: the simple thing to do would be to have PoW without automatic adaptation, but with a slowly rising curve. As such, a coin would never be worth more than the economic cost of the PoW of its creation, and the monetary mass would adapt to its market value to keep it essentially constant (the rising curve would compensate for the improving technology) ; exactly like central banks do. But nobody actually wants "internet money" - except dark markets. People want "digital gold on steroids" to become rich quickly in a greater fool game. My idea is that this is what kills crypto's soul, and that we're just seeing the crypto version of a huge "complex derivatives" market on which people speculate.