This is a great tweet & video about why people are excited about decentralization.
Takeaway: we've centralized so many things on the web that it's getting harder and harder to innovate if you're not one of the top 5 players in the ecosystem. Basically, Facebook controls what you read. Amazon controls what you buy. YouTube/Netflix controls what you watch.
All the hype about decentralization (read: blockchain) is because it has the potential to bring back the excitement of the 90's – the feeling that you as an individual can build, contribute, etc. on the network that is the Internet. I'll dare to say – this actually looks like the Web 3.0.