I'm usually all about NOT handling real money and would prefer to always use a credit card or magicband, except in this case.Especially for kids, there's something about putting your regular penny in and getting it back pressed. It's not the same if you only see the 'after' and aren't more of a direct participant in the process..
Disney seem to be forgetting 'actual guest experience' in so many of their changes.
I can see the children in my family losing interest in this if they aren't involved in the process of putting the penny in themselves.