Like stocks, Cryptos' values are highly based on speculation and psychology regardless of the tech backing it. True investors (smart money) will invest on the tech but also the technology. Think of it this way. Supply and demand. The lower the supply and higher the demand is, the higher the value goes because people are willing to spend more and vice versa. So, if the value goes up because of Internet hype and new investors buying in. Then the price skyrockets temporarily. When that happens, the short term investors sell at high quantities to get a quick return on their investments which drops the prices significantly. As the process drop, new investors buy in and the prices go back up. News comes out hyping Cryptos and high returns and more people buy in and the cycle repeats.