Rationale for simultaneous schedules

Schedules & Zones Create & Edit Schedules
1

It says in the setup article and video to use multiple simultaneous schedules with similar zones in each. Can someone describe the rationale in a little more detail? I for sure have different zones with different needs (e.g., lawn, shrubs, trees), but if the controller has the parameters of each zone and can track the water balance relative to allowed depletion, what is the benefit of multiple schedules?

If I had, say, perennials and trees in one zone with fixed sprays, might I be better off with that zone on a “tree” schedule (infrequent deep watering) and also a “perennial” schedule (more frequent, shallower watering)?

2

I use different Flex Daily schedules for the times that the schedule starts. My lawn starts around 4am in the morning so that it is done by 7:30am. My flowers (less than 10 minutes of watering) start at 8:30am. And since my drip can run during the day time (and can take up to 4 hours), those zones start at 9am. If I had them all in one schedule, my lawn would start way too early.