Lot of people will claim that they can predict the price of cryptocurrencies very accurately, by applying some methods of which Technical Analysis is one.
At its core, the value of a cryptocurrency is determined by the supply available and the demand for it, similar to shares & commodities like gold. In an ideal world this is true, but real-world factors like emotions, market manipulation & insider trading often cause this to no longer apply, or at the very least be distorted.