That's probably not true. When you're just socializing in real life, you're probably sharing all kinds of meaningless "updates" about yourself. Statements, jokes, expressions, etc that aren't important individually, nobody wants to keep records of and you don't care if they get missed. You wouldn't ask your friends to tell you those things because they're so trivial, but they're still how people enjoy each other's company. That's a lot of what friends do when they're together - share minutia. To me, Snapchat is kind of like that but on the internet.