The cards take a beating and before Amazon existed it was much harder to get replacements. We tried regular playing cards, but that only works if every deck has different backs for scoring purposes. I think there was another issue in practice, but that was the main frustration.
I’m not sure if anybody said it yet, but I think a simple figure embracing something would be pretty universal for a “save” and then delete would be that figure rejecting something by putting his hands up and turning its head.