My uncle once found a fake half dollar which he cracked open- turned out somebody had taken a real one, cut the copper out of the core, and replaced it with- guess what- an old-style British large penny!

Sounds like someone didn't know what that penny was made of. It probably contained more copper than he took out of the coin.
With regards to the original post, I don't spend $2 notes that often, but when I do, I love seeing how people react. I honestly don't understand why people think they are so great. I recently lent one to a friend who forgot his lunch money, and he asked me if I really wanted to spend it.