Everybody needs money to survive. Therefore it is very important to detect whether the money you have is real. Imagine how embarrassed it would be if you used the fake money in a public place and were detected by someone else. You can be mistaken for a con. Each country has a different type of money. So the method used to detect it is also different. In some states, you can tell if the money is real if it passes. When making a transaction, some nominal will produce a different color. Take it easy, there are standards that regulate the colors detected on real and fake money.
Not only on the color factor, but paper printed by official money printing has its own character. If the money is fake, you can see it from the color of the pen used on the paper money. Yellow and almost no color can be an indicator. Paper on counterfeit money which is usually the result of a photocopy can be easily recognized if you look at it in detail.
Even though the money that looks real can get you into trouble, it is also not prohibited to be produced. Because there are other needs that require real money that looks like in the process of making films and content of games that require fake money. It would be very unfortunate if you use real money if not to make real transactions right? Many accessories are made from it, which is to make prank and also shows one's love of money. Money that looks real can also be used as an example of learning media for foreigners who need an understanding of the money used in a country.
Someone can not be called an illegal act because it brings prop money which means the money is fake. Because there are no clear rules about producing counterfeit money. But it's clear, if you use prop money to shop at a store, you could be subject to laws governing fraud. You can bring prop money according to the needs that really require you to use it. Even though prop money is made to look very similar to real money, there will always be a way to detect it. So use it according to your needs.