Catherine Zeta Jones isn't an ordinary, anonymous person. Any donation she makes can potentially attract publicity. A discreet, sizeable cheque and a pair of shoes to be publicly offered for auction would probably do more good than the other way around, where news she's donated money might discourage other donors who think it's not needed now they're "bankrolled" by a Hollywood star, and a pair of shoes discreetly auctioned will raise little money and no awareness.
I have no idea what CZJ donated. I just find it weird to criticise her for giving insufficiently or the wrong type of garment. Giving nothing was an option open to her too, and would anyone have given her grief over it?