I don't like that necklace. It's a very disappointing half a million. I was expecting her to be loaded up like a christmas tree.
But OP I think you could apply your argument to just about anything any of us buy for ourselves, even if we have much smaller budgets. Not just jewellery but stuff. Anything. A magazine, a coffee from Costa or Starbucks, a new pair of shoes when we already own shoes, anything.
You could say that since we don't actually need most of this stuff, we'd be better giving the money to charity than getting anything for ourselves.
It sounds like she already gives to charities, as I'm sure everyone on this thread does. But not many people give every spare bit of money they have though, be that 50p or £50,000.
I think you're posting from a good place but it's not just her, it's most of us, she's just doing it on a far bigger scale and I don't think she's done anything to be judged for.
The money she's wearing around her neck would change our lives for years and the inequality can seem harsh, but she's successful because people buy what she sells, and as people have said, if she's paying her taxes and not looking for loopholes, the rest of her money is hers to do as she wishes with.