You're right, people choose to invest in cryptocurrency because it's volatile and you can make more money as compared to other kinds of investment. I'm not an exception. I believe investing in crypto might be pretty profitable if you know what you're doing. Besides, I love the idea of the underlying technology cryptocurrencies are based on, i.e. blockchain, and I want to support it by participation 
I was also fascinated by the enormous profits that cryptocurrency brings. 2017 is not only an impressive year for me but also for everyone, a wonderful year. The motivation for me to invest in cryptocurrency is to believe in a similar thing to come.