It depends on the kind of illiteracy you're talking about, illiteracy can be in different field either in Education which involve not being able to read and write,  financial illiteracy and various kinds of illiteracy. However if you're talking about illiteracy of the person not knowing about cryptocurrency, that person is just like every other person that doesn't have an idea of cryptocurrency and can learn about it haven been taught about it. Everybody that knows about cryptocurrency today at one point in time never knew a thing or two about it, they later learn about it and improved on it.
So the benefit of cryptocurrency to an illiterate person is for that person to learn about cryptocurrency and get the knowledge of it and start investing based on the knowledge he has gotten.