I can discreetly share text, images or videos with a subset of my contacts all at once without bothering them in a private conversation. They all appear in order and in full without some algorithmic trickery, they get flushed after a day or so and my friends can decide if they want to give them a look or not. It's a very nice feature especially for the kind of general stuff that I wouldn't want to personally send to people and clog our conversations.