This seems to be a common occurance. People outside of the US think our currency looks like monopoly money. Meanwhile, many in the US think the same about other country’s currency.
This is not meant to start a thread about whose money looks more real than others - it is meant to ask why this mindset about other countries currencies is so prevelent.
Probably any currency looks like monopoly money (the monopoly money designers seem to have done a good job), but since you’re accustomed to your own, and you instinctively know you’ll get real value for it since you’re exchanging it for real value every day, you just don’t feel that way regarding your own country’s money. Americans believe other nations’ currencies look like monopoly money because they’re so colorful compared to the US dollar, non-Americans notice that the monopoly bills have been designed to look like dollars (with the oval picture in the centure and the frame around it).
I wouldn’t say US money looks like monopoly money. Just really, really boring money. Try Australia for some contrast.