The helmet like version could be a good alternative for the not so sick patience. It looks like there are 3 steps. First only a more oxygen rich atmosphere, like with the extra tube to the nose. The next point could be a slight overpressure to prevent a collapse and push back fluid a little. A last stage would be support of the breathing, by changing the pressure as the patient breaths. This may still need quite some effort to the control of the pressure and atmosphere (e.g. control the CO2 and O2 level).
They looked at the patience later needed classical full machine ventilation - so the system seems to be limited. The hard hit ones may still need the full ventilator as a last resort. It can still be a large help, as the muscles are still used. So easier to get off.
A point could also be the mental side, with the choice of
A) fully depending on the machine in an artificial coma
B) or learn breathing inside the small helmet and with the assistance of the machine
Not everybody may be comfortable with the 2nd option though from the logical side it looks less intrusive. Not everybody is fine with something like a space suite to breath, even if healthy. It could still be more comfortable than a small tight mask.