Peruvian Darkness Powder could've helped Harry in Book Seven

So what happened to the Peruvian Instant Darkness powder?

Harry and the gang learn about it in Book Six: they see it in Fred and George's shop and then encounter it when Draco uses it to escape the Room of Requirement with the Death Eaters near the end of the novel.

Why don't they take a supply of it along with them in Book Seven? I would think it would have come in very handy on several occasions: in the cafe just after they escape the wedding; at the Ministry; during the break-in at Gringott's; in the woods when they are being grabbed by the snatchers; even at Malfoy Manor.

Isn't it odd that they don't take some with them? Even more odd because the Weasley twins give Harry a large box of their products for his birthday at the start of The Deathly Hallows (which might have included some of this useful powder) and Rowling even goes so far as to tell us Hermione packs Harry's presents before they leave the Burrow.

I've also often wondered why a great many more people aren't seen in the final book wearing the Weasley's shield clothing, which Fred and George show to Harry on his tour of their shop in The Half-Blood Prince. Remember? They even tell Harry that the Ministry of Magic has placed a massive order for the hats, gloves and other pieces of clothing that have been charmed to repel minor spells?

I know, I know. We can't expect J.K. to be perfect but...