Well, I mean, engineers want lots of things. I suspect that most engineers *really* just want to call `numpy.random.seed(8675309)` at the start and never explicitly pass around separate streams. There's an upside to that in terms of code simplicity. There are also significant limitations and constraints. Ultimately, the upside against the alternative of passing around RandomState objects is usually overweighed by the limitations, so best practice is to pass around RandomState objects.