WTF IS FINALITY?

Summary from the TLDR Crypto newsletter

Finality in blockchains refers to the point when a transaction becomes permanently and irreversibly part of the ledger, much like how wet concrete eventually hardens into a solid state. This article uses this analogy to explain how different blockchain systems, like Ethereum and Bitcoin, achieve finality — Ethereum through validator consensus over epochs and Bitcoin through the longest chain rule in Proof of Work, though Bitcoin never truly reaches a final, irreversible state.