Public speaking primarily reveals what about the speaker hobbies, personality, idiosyncrasies?

First, does public speaking reveal the person's hobbies? It can, if the person is talking about the hobbies, but it does not need to, such as when a person is speaking in favour of a political candidate.

Now, I am not too sure whether there is a difference between Personality and idiosyncrasies here - idiosyncrasies being the more unique aspects of personality.

I would say that "personality" is the better option - as public speaking reveals the unique and the not unique aspects.

Hey i rrr was the time