Why is black powder used in modern military munitions?

I was surprised to read in [this recent WSJ article about a black powder shortage](https://www.wsj.com/articles/the-u-s-military-has-an-explosive-problem-6e1a1049?page=1):



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> Today, [black powder] is a specialty commodity with few commercial applications—mostly for rocket hobbyists—but it’s still used in more than 300 munitions, from cruise missiles, to bullets for M16 rifles, to the vital 155mm shells. In each case, a small amount of black powder is used to detonate a more powerful explosive packed in the same bullet or missile. A 155mm shell for a howitzer, for example, will use half an ounce of black powder, lodged next to 26 pounds of a more powerful explosive.
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That's describing black powder being used as a detonator/primary explosive, which I had always understood it could not do because it is strictly a "low explosive" meaning it can't develop a supersonic shockwave (VoD). I have never seen black powder listed as a [primary explosive](https://en.wikipedia.org/wiki/Explosive#Primary). So is the article mistaken about its use in modern military explosives? Or does black powder serve some purpose other than detonation in those munitions?


