It might be of use for a couple of reasons. One, you can compare the purchased material to that which you're trying to produce. Second, with the purchased mat

It might be of use for a couple of reasons. One, you can compare the purchased material to that which you're trying to produce. Second, with the purchased material you can assemble and test-detonate a bomb, which not only causes other countries' intelligence agencies to question the value of their sources but gives you leverage in future negotiations.