Community Submission - Author: Obasi Ifegwu
Finality is the assurance or guarantee that completed (cryptocurrency) transactions cannot be altered, reversed or canceled. The latency level of a blockchain will ultimately affect the chain's finality rate.
Finality is used to measure the amount of time one has to wait for a reasonable guarantee that crypto transactions executed on the blockchain will not be reversed or changed. In other words, they will not be lost (orphaned). Finality is an essential feature for ventures accepting cryptocurrencies because waiting endlessly on a blockchain network can have a high adverse effect for businesses or enterprises that accept cryptocurrencies as a means of payment. When creating a payment system, to be effective, it is crucial to have low latency.
To put this in perspective, if you were to have to wait for 10 minutes every time you wished to purchase anything, it would quickly become very inconvenient to go shopping.
Also, in the financial sector, companies need to know, within the shortest possible time frame if they own certain assets.
When it comes to blockchain technology, transactions are termed immutable due to its finality nature. However, most blockchain protocols only show a probabilistic transaction finality — that transactions are not automatically or instantly final but become more and more final over time.
The amount of time it takes a blockchain network to confirm a transaction (latency) determines the nature of the chain's finality rate. Below is a table that shows different blockchain networks and the duration it takes them to reach finality: