The basic underlying idea behind the use and creation of cryptocurrency is to present financial freedom to everybody no matter where you find yourself in this world. But the volatile nature of these digital currencies got me thinking, what if the whole idea of blockchain and cryptocurrency is just one giant Ponzi Scheme? Within a short period of time, there have been about thousands of cryptocurrencies created. Majority of these digital currencies are either trying to solve problems of a particular cryptocurrency by presenting solutions they think can help improve financial freedom. This usually gets me wondering and thinking. If you don't agree with me on this, please share your thoughts... 
Your assumptions are quite ridiculous to think cryptocurrency is a ponzi scheme. I think you should spend some time researching and reading about blockchain technology, this will help you understand some basic features of this technology. The volatile nature of cryptocurrencies is as a result of the decentralized nature of blockchain technology, giving users the opportunity to set their own price at which they want to trade their coin. This is the main cause of the fluctuations in the market value of a particular crypto coin. Cryptocurrency is never a ponzi scheme.