This seems like a sensible but odd carveout. The law is essentially legalising e-scooters on shared paths, and bike lanes on roads with no more than 20km/h. The proposition does not allow them on footpaths, which you’d think would be the most relevant place. Personally, I’m surprised they wouldn’t allow them on footpaths but no more than 5 km/h in heavy pedestrian areas (anywhere a car would have to do 40 km/h or less), especially since you could potentially require shared e-scooters to enforce this speed with GPS.
They are good for multi-modal transport in particular, since you still can’t take bikes on buses (at least not in NSW). Hopefully that will change in the future, too.