I would also add that in ControlLogix, the continuous task has the lowest priority of all. I/O is also a task with a priority of 6. People use the continuous task because that's what they're used to from PLC-5/SLC-500, because Studio5000 generates one by default, (unless you use a "P" model which generates the PlantPax tasking model) & because they are too lazy to read about the hardware they're programming. Case closed.
IMNSHO, Rockwell has done a poor job of communicating the advantages of this model, which is after all based on IEC 11631-3