> It would allow using full spectrum lighting, and would be easier to selectively filter.
Making a broad spectrum IR filter is far easier than a notch filter for a single visible wavelength. In general it's harder to make more selective filters and an IR filter can be much less selective because the IR band is so large and far away from any visible light.
Also the infrared version would allow using any color background including black, and the on set lighting would appear to the eye exactly as it does to the camera. With the sodium vapor process the bright yellow background would make everything on set look different in person because the eye wouldn't be able to subtract it the way the camera does.
Yes, you would need a filter on any incandescent light. But this is also true of the sodium vapor process. Actually I'm not sure anyone makes a sodium vapor wavelength notch filter suitable for putting in front of an incandescent light. Consequently, as seen in the video, they restricted themselves to special LED lights that emit essentially only three wavelengths. These are very much not full spectrum and will not produce natural colors for some materials. And they had to completely block all windows, whereas for IR you could just install some IR blocking film on the windows and still use natural sunlight.