If it is enjoyable for the kids, it is okay. But I don't see the way that it is can be a fun activity as playing play money. However, it is my suggestion or self-opinion, you can do it whatever you want. Your kids are yours, I don't have the right to force you. I am here just to give a suggestion, so if you think it is good, then you can consider it. Well, up to you, bro.