Regardless of whether it is going up or down, the fact that its value fluctuates so much is a pretty good demonstration of its utter failure to fulfil the role of a currency.
As in, why am I ever going to spend any of the stuff if I think it is going to be worth twice as much two weeks from now? great for a few investors, also a demonstration of the total failure of the ideology behind it.
It's misclassified as a currency. Financially, it operates as a commodity. You can use a commodity as currency as well of course, gold and silver were for most of the existence of recorded history. And oil is now to a point.
That Bitcoin swings wildly shows the effects of a limited number of participants in the commodity market buying and selling as happens in other commodity markets, but the long-term rise also demonstrates what has happened to global fiat-based currency systems, especially from 2008 onwards. Right now since the beginning of the year, I could've had sheets of plywood as my personal currency to buy items with, and would be doing pretty well.
(Disclaimer: I do not invest in Bitcoin or any other e-coin.)
But it is a commodity of what? At least gold and silver are physical objects that have established uses. Bitcoin doesn't.
When you trade gold or silver you are at least buying (in theory) something physical. Bitcoin and other cryptocurrencies aren't like that.