The main tenets and value proposition of blockchain. What do you say to people when they ask "Why does blockchain matter?". Please come contribute!

1. Disintermediation - This is the HUGE use case of blockchain and why most of us are here. Disintermediating the financial system and financial products. The ability to allow two parties to directly interact peer to peer without having a middle man. This reduces corruption and abuse of power and makes for a truly global currency. If you need to move to another country, you don't need to set up a new bank account if you have blockchain. You don't have to find a new bank in a new country, you bring your crypto account with you! Impossible to do with traditional fiat.
2. Data Provenance - Once data is recorded on the blockchain it cannot be tampered with after the fact. This is huge for supply chain, and basically anything produced. The ability to walk through transactions on chain to see when and where something was produced or located. Digital veracity is a very interesting use case.
3. Decentralized Identity - The idea of owning your data and identity is powerful. We do not own our Reddit usernames and data, Steam games, Gmail emails, all these things are intermediates through a centralized system that can bar us access at any point. If steam bans me I lose access to thousands of $ worth of games. If gmail bans me I lose all my contacts and emails. The ability to truly own your online digital identity and products would be huge.

What are your thoughts on this? What do you say to people that are skeptical and ask, "Why blockchain?".