This thread is amazing. Surprised to see that people are knee jerking against these with much the same arguments as you get against bikes and increased bike infrastructure.
They are the future and there's no reason at all that they can't coexist on the roads along with bikes and have the same status. Calling for them to be licensed and for extensive training before you go near one is equivalent to calling for all bikes to have numberplates.
I agree with this person, not the whingers.