No, really, changing coin designs is for the same reason that sex exists and works so well. So this is really news about sex and people are usually pretty interested in sex, right? That old pound coin was pretty secure when it came in 30 years ago too (and I feel dreadfully old as I can actually remember than happening. So, we've got to keep changing the coin and note designs to keep ahead of those forgers. Thus money changes, note and coin designs, are exactly like sex.

Source: Forbes March 28, 2017 15:45 UTC