I hypothesize that the runup in both ETH and BTC ('cuz they've both climbed) is due to the fact that the finance intelligentsia have started expressing legitimate concerns that the Fed might pursue Negative Interest Rate Policy (NIRP) within the year. I saw a graph somewhere that pointed out something like a quarter of the world's currency is already under NIRP, with Japan and Germany leading the way. Bonds are in the shitter. Commodities are hammered. Oil is a losing proposition. The main advice being offered these days is "go to cash" or "go to gold" and when "go to cash" becomes a losing proposition rather than a gaining one, "go to gold" wins. Cryptocurrencies have all the attractions of precious metals and the ability to be used as currency. BTC kicks the shit out of gold. And if you're hedging, ETH is a penny stock that jumped to six bucks while you weren't watching and holy shit you can buy a lot of it right now and if it does what BTC did, you're gonna be filthy fuckin' rich, who cares what interest rates the Fed charges for interbank? That's my theory, anyway.
There's also a lot of Greater Fool Theory going on here. For me, it's a student loan moonshot - I'll hopefully be able to use it to make a significant dent in my slowly accruing student loans. Also, I find the /r/ethtrader daily discussion threads very entertaining. It's like a nerdy version of horoscopes.
I told my wife that as soon as ETH hits $1k per I'm cashing out and buying a mansion. She laughed.
It will happen.
I think I've mentioned before, my favorite statistics professor decorated his office in fortune telling memorabilia to remind people he consulted with not to trust him too much. I wish more technical people were like him. Those required communications classes drill into you that you need to work on establishing your credibility, when we usually have credibility be default and need to make sure no one is more certain of our work than we are ourselves.