The status quo is that the first cartridges/cannisters were designed for the Dolphin and the latter then adapted for the Azimuth. The cartridges were therefor rated originally to 5 bar (40 msw - same as the rebreathers they were made for). A while ago that was oncrease to 6 bar/50 msw. The current duration for the Dolphin is 210 minutes.
However, testing of the cartridge was performed at 40 RMV, 1.35 LPM CO2 injection, 13 degrees C/55.4 degrees F and 1 ata. The problem of course is the 1 ata, as ambient pressure plays a considerable role in duration (example Inspiration: 180 mins at 20 msw and 88 mins at 100 msw, both at 40 RMV, 1.6 lpm CO2 injection and 4 degrees C/39.2 degrees F)
As you may know, the new Dive Rite O2ptima uses the same cartridge in a Micropore cannister (the latter is different to contain the needed CCR electronic bits). Additional testing to 100 msw has been promised, and hopefully will be available publicly.
This should show the true potential of the cartridge system.
There is a bit of gas space around it, hence some insulation, the rolled grid is designed to always be 'perfectly packed'. So there is a fair chance that performance matches or surpasses the stock cannister even under same testing conditions. When Steam Machines tried a like system years ago they noted a better performance in axial scrubbers, but still less efficiency than radial or annular axial designs.
Two other big advantages are the extreme ease of use and almost no dust (reduced chance of caustic cocktail).