Right now, these blockchain currencies are traded just like expensive wine, art or gold bar. It's a speculative money game. We can't use wine or art to buy some food for today. Most people don't even run the full node themselves. They relies on somebody else's node. In good term, they are investing, in other words, they are gambling.
It's just sad seeing a lot of resources and some brains are wasted on these gamble.
How could this be happened? When bitcoin was announced and it's first implementation was actively developed by someone or some group known as Satoshi Nakamoto, it was just a technically interesting non practical piece of attempt. But now... it's just a mess. Had I mined bitcoin in early days, I could be a billionaire. But the same thing can be said on buying the gold bar. It's not that technically interesting.
The first P2P boom invented a lot of practical services. File sharing, web hosting, audio and video streaming, video chat and all. They are all pivoted to central system for efficiency, but some services gained a few years of early head start experience thanks to the P2P. What blockchain achieved so far? Nothing. It just invented another gold bar. Totally useless but some people believes value in it.
I really wish people wake up and spend precious time and resources on something that introduce real value to the world. Blockchain? Wake me up if proof of storage space become practical.