I thought the YO app, was stupid and pointless till I realized it was used to warn Israeli citizens of missile strikes!
Now that app is everywhere and seems to have mastered the concept "notification-is-the-message" philosophy.
I guess there's a market for anything.
Unless you want to suggest there is literally no other way on a device capable of running the YO app to send a message to a group of people (which would be an absurd thing to assert), then I will stand by my statement. If it's useful, it's useful in spite of its own stupidity, not because of its own brilliance.