Forks are typically conducted in order to add new features to a blockchain, to reverse the effects of hacking or catastrophic bugs.
Forks require consensus to be resolved or else a permanent split emerges.
[10][4] Hard forks splitting bitcoin (aka "split coins") are created via changes of the blockchain rules and sharing a transaction history with bitcoin up to a certain time and date.
The fork adds support for Schnorr signatures, and improves functionality of smart contracts and the Lightning Network.
[14] Advantages: Three hard forks were created by "protocol change" definition: