As only a minor nitpick (my excuse is that this is my day job), you've got it the wrong way round - REDCODE is actually storing data as RGB, whereas 'every other camera' is almost certainly using a MPEG-based codec and storing it as YUV with chroma subsampling - somewhere between 4:1:1/4:2:0 to 4:2:2 depending on the camera in use.

As with any lossless compression, it's a compromise between having almost all of the data shot to work with versus pretty much having to always do a full grade on any content you get and the additional online storage space needed in post-production.