So what is this good for? No unpredicatable result happen, right?

 

MQL5: The behavior of the OrderSend function during order placing, modification, and canceling has changed. The changes only apply to orders sent to external trading systems. In earlier version, OrderSend function control was returned after the order has been successfully placed (handled) on the broker's server. Now the control is only returned after the broker's server receives a notification from an external trading system notifying that the order has been successfully placed in that system.

The below diagram shows the previous (red arrow) and current behavior of the function: