Lol: a simple word?

People often type lol or brb etc etc. And so do I. But 98% OF PEOPLE WHO TYPE LOL ARE JUST TYPING BECAUSE THEY LIKE TO. Lol, is not really considered "laugh out loud anymore" and just: hot home from school lol and lol yeah. But why do people type lol in the first place instead of saying something else. What's your opinion: is lol overused, or part of dictionaries?