Fibre reinforcement in the mix would probably allow you to build without rebar
Quite likely stainless steel needles could be included in the mix as reinforcement – both fibres and steel needles are options in readymix concrete.
No reason why twin skins with a third middle core of insulation could not be devised in a further development of the machine.
However, I feel the modular, or prefab, route is more likely to gain ground in the UK. Plenty of development in this sector already.