I have a wide variety of landscape/garden types. Just in my grove, I have mature Avocado and mature Citrus, and baby Avocado and Citrus. I have four zones just for that. A 2 year old Avocado might need 10 gallons per day in the summer, and an 8 year old might need 40 per day. I’ve already measured my heads for flow rates and to make things simple they are all set roughly the same, so I vary the amount of water they get by the run times. Putting them all on one schedule then tinkering with the flow rates would be infinitely more difficult. Some trees need a deep soak every 10 days, other trees need a lighter soak more frequently.
Then there is the palm trees which need much more frequent watering than the grove does.
Next in the garden, I have multiple different beds with different needs. Some drought tolerant plants that need infrequent watering, some newly sowed lettuce than needs to be kept moist (3 soaks per day in the heat), tomatoes, blueberries, strawberries and most other garden vegetables that you typically use to make salads. 16 different raised beds each with a different crop in it, all with their own sets of needs. Some needs are similar and could be combined, but as plants in a specific bed grow and their needs evolve, if I can’t customize that one bed’s run time, I’d have to rip out 1/2 gph emitters and replace them with 1 gph, then 2 gph, and hope thats the right amount, or add emitters then potentially remove them . Instead I use 1 gph emitters for every bed and adjust run times based on that beds water needs. Not all drip beds should be given the same amount of water, and its just far easier to edit run times than to tinker with flow rates of emitters.
I get if I had a large yard of grass, with a lots of zones because of max pressure/flow per zone, then I could slam them all into one schedule and let Rachio sort them out. But I have a lot of different water needs and a very high water bill, so I want to water every zone as little as possible to stay healthy. As I observe one bed’s plants needing more or less water, if that bed is on the same schedule as every other bed, again I’m back to tinkering with flow rates of drip emitters vs simply tapping a few clicks on my phone. Isn’t this sort of why Racho was invented, to make this easy?
BTW, you have three types of landscape (lawn, flowers, drip) and you mention having six schedules. I will eventually have about 22 zones and probably about 16 or 17 different schedules based on the needs described above. Trust me, where I can combine zones because the water needs are similar I certainly will, but right now each new bed I plant gets its own schedule and the grove will have at least two schedules until they are all the same size trees.