It has a regular chat type system too, but it's "optimized" for sending pictures easily. They probably send those messages to maintain a streak (how many days in a row you've sent pictures to each other) or because it lets them send it to multiple people at once instead of going into each chat individually. The pictures are deleted after two views max, and messages are deleted as soon as you close them by default, but you can save any message to keep it in history; you can also change the chat settings to only delete them after 24 hours to make it easier to follow a conversation. I prefer other apps, but it's my only way to talk to a handful of friends.
It has a regular chat type system too, but it's "optimized" for sending pictures easily. They probably send those messages to maintain a streak (how many days in a row you've sent pictures to each other) or because it lets them send it to multiple people at once instead of going into each chat individually. The pictures are deleted after two views max, and messages are deleted as soon as you close them by default, but you can save any message to keep it in history; you can also change the chat settings to only delete them after 24 hours to make it easier to follow a conversation. I prefer other apps, but it's my only way to talk to a handful of friends.