Most kids are clueless with tech to be honest. Yes they know how to use it, but they have no idea how it works behind the scenes. This has pretty scary consequences on how they are easily manipulated or scammed.
Some of them are very smart, sure, but on average I'd say they are less tech savvy than Gen X and millennials who grew up at a time you couldn't use computers without some kind of knowledge of how it works (and smartphones didn't exist).
I'm not sure what the business model is here (I have no interest in iMessage) but unlike the previous ones this solution doesn't require a Mac mini farm. Messages are sent directly from the Android device.
So it doesn't require a monthly fee to be profitable.