Bitcoin is a weird relic of the angst of the Great Recession. It was created because a bunch of right wing skeptics of central banks who thought that replacing government backed fiat currencies with their own inherently deflationary currency...which is also a fiat currency, hilariously...was the future. Almost a decade later, the central banks have pulled the world out of the worst recession since the Great Depression into a booming world economy with low inflation. So the entire premise of currencies needing to be decentralized is sort of a farce. Along with it the initial point of these things.
But that doesn't matter today. What matters is that these currencies have found utility in black market transactions and have lived on past their best by date in this capacity.
Now the technology that these currencies are built on is ingenious. Blockchain. This technology is novel and will live on. What happened is that the original right wing crypto evangelists never gave up their "antifiat" crusade and blockchain emerged as a technology that everyone wants to invest in.
People, for whatever reason, think that investing in a product USING a certain technology is the same as investing in that technology. Blockchain had no patents, so investing in it is impossible.
But because of these factors, people all of a sudden last year decided that Bitcoin, Etherium,Litecoin,etc were going to change the world banking system and it began to become more valuable. This caused speculators to notice. It began to snowball. A bubble formed. And here we are.
It's been fascinating to watch.