I don't think anyone cares or should care about easy-to-break encryption. Encoding and decoding your messages has a cost, there needs to be a benefit beyond "looking cool".
I have to agree, but I was looking to limit the "cost" by making it easy and fun. I could see the demographics, most of them had time to kill. And with young people, you never know what will be cool, fashionable or viral. Easy-to-break is subjective too. Sibling, parent, teacher, advertiser, somebody looking over your shoulder? They couldn't break it. I think every generation has something like this, a Cracker Jack decoder ring, passing notes in class, some 1337 letter generator.