AIUI California minimum wages:
A) fast food employee: $20/hour
B) other employee: $16/hour
C) delivery gig worker: $19.20/hour plus $0.30/mile (but only for the time you're actively on a job)
I guess they did the math and figured out that C is cheaper than A. If the demand for pizza delivery workers is spiky, perhaps it makes more sense to link the costs to the actual output (# deliveries).