I agree about your minimum, so long as it is (as you suggest) definable because I disagree that it is “useless to water for 1,5 minutes”. Some of my zones are set to about that under 100% conditions! Still, those then get cut down to something like 3 seconds and that really is useless (that hardly fills the lines).
Drip has vastly different requirements and weather adjustments than sprinklers. Indoor has vastly different requirements vs outdoor. The more fine-tuning we can do on an individual basis, the better.