They're scooters, not bikes. There is a huge difference. The handling of those things in the wet or at any speed, with those little wheels, would be rubbish.
Not sure we will ever see them banned, they are not a bad way for people to get around, but there should be strict laws on the speed they can do. Some of those things can get up to quite high speeds, and they are not safe for the rider or anyone else around. Limit them to 25KMh and any seen going faster get confiscated.
We also need to sort out how they are dealt with. Clearly scooters are unsafe on footpaths, and they are not a road vehicle (unlike a pushbike). So what do we do? Not an easy question, maybe allowed on footpaths with a speed limit of 10KMh (bear in mind that in Victoria bicycles are not allowed on footpaths unless the rider is under 12 years old, in Qld they are allowed on footpaths). But some sort of decision needs to be made about where they fit, are they road vehicles, are they recreational vehicles?
DS