That's an interesting question. I am not sure if there are any further detailed answer to your question, but as far as I am concerned as a Korean, let me try to explain about it. It basically is used to inform and rather sound like an order. You don't really hear that kind of sentence on a daily basis unless you are talking to older people with high authority. It isn't really informal, whereas you've got to be careful when to use according to the person you are talking to. Also, i would not say it is rude as long as you don't say it to older people than you and someone you are not close to. Hope this helps and have fun with learning korean :)