Scheduled transactions are transactions that you sign now and take places in the future at a given time. In the history of Ethereum, signing a transaction and the actual execution of the transaction are often considered to happen almost at the same time as long as the transaction is proven valid. The miner would immediately include your transaction in the block if you subsidize enough gas. However, there are cases where you want to pre-approve a transaction and let the transaction be automatically executed at a given trigger (time, event, etc.) This is when scheduled transaction comes into place.
With scheduled transaction enabled, you may enforce a logic (currently, we only support time configurations) as the trigger and sign the transaction beforehand. After you sign once, the rest will all be taken care of automatically.
This enables use cases such as recurring transfers, payrolls, automatic integration with DeFi protocol, etc. In the future, we aim to support more logic-based triggers such as on-chain events, protocol interactions, account states, and so on.