'MIRI' works in the search field when electing a charity to get 0.5% of your https://smile.amazon.com purchases.
If one of the EA organisations would go to Visa, I don't see any reason why they shouldn't be able to negotiate at least as much money as a good cashback card.
So why haven't other charities which have got cashback cards succeeded in doing this?
'MIRI' works in the search field when electing a charity to get 0.5% of your https://smile.amazon.com purchases.