For home cheese production, I think the cellular disruption is minimal and it is a tidy solution for folks dealing with DVI packaging designed for much larger batches-- less contamination risk and more accurate measuring. Most commonly, folks let the cube defrost for an hour in advance of use. It is really no different than using a dried starter nearer it's use by date (which clearly works, two years! wow!!) and if one was really worried about it, could add an additional IU to compensate (I would not recommend, but just making the point).
Using a DVI in live milk under normal conditions already results in deviations from the lovely acidification curves on the datasheets and I just don't think this method creates a material difference -- it is certainly a zillion times less impact than, for example, the seasonal changes in milk (which is on my mind as the cows I get my milk from went out to pasture two days ago and it is all change in the vat!!)
But this is a geek out to be sure, so apologies to Kirbybil!! Just try things that you think are right and, above all, have fun with your cheesemaking!!