bitcoin is a currency that is being traded like a stock. Something used in a way that it wasn't intended towards is the definition of a bubble. Could bitcoin (or any crypto) work long term? Sure. Is it entirely based on speculation though? Right now absolutely.
Also keep in mind that December through Feb/early March is almost always the busiest time for markets like crypto and OTC stocks, which follow similar types of volume and price spikes.
Casual Revolution 2007 - 2016