I don't think you can do everything in the astral realm like you can in a lucid dream. There are some things you can not control in the astral realm.
Yes there are differences between a lucid dream and astral projection .In astral projection it is taking place in real time for waking life, the only difference is that you are not physical anymore however in lucid dreaming what you are expriencing is a hallucination that you can control at will. What you see in astral projection is something that is actually happening while when you lucid dream there is nothing truly going on.

I would choose to astral project because I would like to truly have a different way of expriencing Reality and to know that it's real, to know that I actually gain something in this Reality and to destroy theory of mind.