Why do you think virtualized == toy? Is MirageOS a toy too then? They have no chance of ever getting enough device drivers to be able to support all the hardware out there. Running virtualized makes sense, and it's not a big performance hit.
A possible reason why "virtualized == toy" is that the virtualized system simulates certain specific hardware. The OS provides drivers for that hardware. But it hasn't been validated on the real hardware.
We don't know whether that is the case here. If the authors get a real box that has the same peripherals as the VirtualBox, and bring the OS up on that, then this "toy" argument can no longer be made, in any case.
