By the description these are lyophilized (freeze dried) samples and there is some possibility they could still be viable. This process is used with bacteria as well and is how bacterial and viral samples are shipped to other research facilities. The writer uses the term storage room but I doubt very much that this was some broom closet.
This might be useful since the concept of smallpox being truly eradicated is ridiculous. There are many parts of the world remote enough still have carriers who are dormant and we could never be assured that all of the samples throughout the world were indeed destroyed. Having samples might be useful in recreating vaccines for it.
One reason for retaining the remaining stocks of smallpox virus is for the purpose of making vaccines. However, we do not actually need smallpox virus to make a vaccine. All we need is vaccinia virus, which is commonly used to make vaccines. Everyone who is immune to vaccinia is immune to smallpox.
I will certainly be looking forward to the viability test results on these samples.