Timothy B. Lee has a good short essay on that question, here is one piece of it:
Between January 2013 and today, the amount of money invested in Bitcoin startups has grown more than 100-fold. Even after 2014’s declines, Bitcoins today are worth 20 times what they were worth at the start of 2013. The number of Bitcoin ATMs has gone from 0 to 342. Yet during the same two-year period, the number of Bitcoin transactions each day has not even doubled.
In short, there’s a lot of excitement among Bitcoin hackers, Bitcoin investors, and other insiders. But normal people are hardly using the network at all.
Recommended throughout, he argues that 2015 will be a make or break year for Bitcoin.