Getting rid of pennies is a good use because you can save materials, you can save thousands of money, and no one ever uses pennies
The <em>magi</em> didn't, technically, <em>invent</em> anything. They were wise men or magicians and probably astrologers. Because astrologers watched the skies and could predict where the stars and planets would move to, they were considered to be able to foretell the future.