I've never thought of this, but wow it seems so true. Whenever a new batch of emojis come out, my friends start sending them which entices me to go update immediately.
Perhaps they're onto something here. Clickbait in the service of security? The black hats are already using the darker side of mass Internet behavior. "Secure your computer with this one weird trick!"
This is the only way I'm able to convince my family to upgrade sooner rather than later. Nothing quite like square-box-triggered FOMO to force an upgrade.
One wonders - how long can updated emojis continue to motivate people to upgrade? Diminishing returns will have to kick in at some point. But there is still more room for innovation in the Messages app.