To bring this back to the actual topic, I'm pretty sure Edwina was well-aware of how her money was viewed, given her aristo father had somehow managed to 'overlook' the "Catholic-Jewish-new money" thing and marry her mother.
Somehow.
Enough for that, not enough for her father to view her as worth anything, not enough to save her mother's life, and not enough for her stepmother not to be a racist b*tch to her (to quote Dickie), and I'm sure many others to take the same attitude as well.
Perhaps it's not much of a surprise she didn't care for rank and gave the money away so freely later on.
Or perhaps she saw marrying so close to the royals as a little bit of extra armor.