Well then you are not talking about the OP, which i was, so we are at cross purposes.
However, I do think it is a good thing for a child to understand that there are different levels of need, and poverty/wealth, yes.
It can hardly be hidden.
DDs primary school is an eclectic mix of the seriously struggling and the Birthday Pony brigade. We are somewhere in the middle. I believe that it is a good thing that DD understands that she is 'lucky' to have what she does, so that she doesn't become spoilt or grasping. She has friends on both sides of the fence so to speak, she enjoys spending time with all of them.
She knows that when her class asks for a 'voluntrary' contribution to a trip, we always pay double. She knows we can afford to do so, and why we choose to do so.
She knows that when homework calls for something to be printed off the Internet that her very best friend will come to ours to do it, because her mum doesn't have Internet at home (and yes, they could go to the library, but it's not that easy with younger children in tow).
By the same token she understands that her friend with the pony at the bottom of her garden is far more wealthy than us. She knows we couldn't afford one, so doesn't well hardly ever ask.
She knows how her father grew up, and knows how he got out of the poverty trap. She actually enjoys the stories her Nana tells her, and is shocked by some of the things she hears. At 7, she has an amazing understanding of the world, and also understands that real poverty is a great deal worse.