How Does ‘Finality’ Address the Double-Spending Problem in Proof-of-Stake?

Finality in PoS means that once a block is finalized (usually by a supermajority of staked validators), it is irreversible and cannot be reverted or changed. This provides a strong guarantee against double-spending because the attacker cannot create a longer, alternative chain to reverse a transaction.

Once finalized, the transaction is permanently recorded, unlike the probabilistic finality in PoW.