How Does the Transition of Ethereum to a Full PoS System Impact Its Finality?
Ethereum's transition to a full Proof-of-Stake (PoS) system, known as The Merge, introduced absolute, faster finality via the Casper FFG mechanism on the Beacon Chain. Unlike the previous probabilistic finality of PoW, a block confirmed by a 2/3 supermajority of staked Ether cannot be reverted without the attacker losing their stake (slashing).
This greatly enhances security, certainty, and reduces the risk of deep chain reorganizations.