On a space station, every air exchange filter, every bite of food, every gallon of water is potentially important.
There, fixed that for ya.
important should something go wrong with the established system. But right now, being un-manifested and unrequired for normal operation, it's not important
The word you should be using is "useful". And depending on the details of what they are actually sending, that may not be true either. For all we know it's 1200pounds of deodorizer.
especially now that there's only one proven system operational.
Which "one" is that? the russian Progress? the ESA ATV? or the Japanese HTV? all of which are proven.