Direct Democracy means that it is a form of government that is ruled by the citizens. All the citizens have equal decisions
Their main advantages would be that the citizens propose the laws and the leader decides if it is a good idea or not. Not only that it's time-consuming. A good example of this type of government would be the United States of America. They use this type of government. And they known to be one of the strongest.
Their really isn't any disadvantages besides that the voter's decision has a very high chance of not creating the new law.