Sometimes you need to make an Ethereum payment transfer at a specific time that may not be very convenient to you(middle of the night, airplane flight, etc). With Ethereum Chronobot, you can submit signed transactions to be executed lately at the time you choose. In the case of ICOs this might be very handy, because you can prepare everything and schedule the payment exactly when the ICO starts so you minimize the chances of missing it.
Chronobot will broadcast your transactions to multiple nodes so miners can pick it up very fast. There is no need to keep your internet connection up or wallet open, once you have submitted to Chronobot, everything will be done automatically.