Only Speculation made by trader or real importance of Cryptocurrency has been found?

In janury, according to Coinmarketcap, the global capitalisation of all cryptocurrency was in January less than 20Billion $$
at the time of this article has been writted, the marketcap was $51,632,164,116!!
Only 4 Months to make a return of 250% of your investment if you were holding Cryptocurrency.
Is there any risk associated to this quick grow?
is someone playing with price for his benefice?
Is the world opening a big door to Blockchain startup?
Is it time to invest massivly in Cryptocurrency?