Now that it comes to my mind, was your intention of this thread to encourage us to introduce bitcoin to people we know and make us think of the best ways to answer these frequently asked questions?
I'm kinda new to bitcoin my self and I've already been asked some of these questions a couple of times when I introduced Bitcoin to my family and close friends. I haven't really given them much thought and your post made me think about them.
I have edited my post. It's ok if you're looking for better answers. I not being a native English speaker find it hard sometimes to find the right words to explain stuff.
I'm adding your answer as the first part of the answer to the question, but I'd expect some more from others, as well.
It may be better if you state this in your first or second post so that other members won't just skip the answered questions but instead read their answers. This way new members may actually learn a thing or two.