One of Bitcoin’s most valuable features is timelocks. The feature, which existed since the first release of Bitcoin, enables users to create transactions that are invalid (unspendable) until a certain time has passed. In 2015 and 2016, a handful of Bitcoin Core developers introduced more advanced levels of timelocks, enabling users to create timelocks for individual Bitcoin outputs rather than entire transactions.
Timelocks also provide the base and infrastructure for a variety of smart contracts and projects built on Bitcoin. Layer two projects like Lightning Network rely heavily on the development of Bitcoin’s timelock features. Companies like Particl also use timelock features to create escrow services for clients.