Well, scientists from Kew Millennium seed bank or USDA would answer better :) but I ll try. First, testing seeds with uncertain behavior is important because for some endangered species we cannot really say if their seeds are orthodox or not. Second, there is an interesting issue about long-term storage behavior of seeds in cryo. Third, some seeds defined as orthodox may have unusual rage of optimum hydration window (as it happened with some Salix spp, for example). So we`d better know how to handle them.

Orthodox seeds which come from elite genetic stocks, varieties, wild and endangered species, tree spp. make good candidates for cryostorage. These categories of genetic resources, once lost from the nature, are very difficult to reconstitute and/ or difficult to regenerate when viability is slowly lost at seed genebank temperatures of -20OC. Hence it is ideal to store all these resources in LN. 

can I please some publications which prove this cracking of seed coat / decline in viability on cryostorage