That is part of it. Tests aren't usually run for show; you're trying to solve a problem or determine a most efficient way of operating.
Except in this case, it's ALSO a show. It's a product demo. The better results they can demonstrate, the more buyers they will have line up for their wares.
Think of it like this. If you're a third world dictator, how much would you care that North Korea is researching nuclear weapons? Meh. What if they had working weapons? For sale? Did that get your interest?
For a long time, we cared about their research, and tried to bribe them out if it. If those bribes are no longer on the table, then they have to move to the next stage, which is to make money off of the weapons directly. They aren't making nukes to use on South Korea or blow up Seattle. They're making nukes to scare us off, and to make money. The North Korean leaders want to live, and they want to live a long time; fat, dumb, and happy. There's a LOT of money to be made being the world's nuclear weapons Wal Mart.
But first, you need prove you have a working product. Hence the tests.
Makes you wonder about the $137 billion in treasury bonds that were being smuggled in Italy.