I don't know about that, except the left hand usually has the more complex piano part. I'm also a lefty who uses the mouse with the right. It sounds like a lot of people use the mouse with their "other" hand.
My lefty gripe is crossword puzzles. All the clues run down the left-hand side of the puzzle, so you have to lift your hand to read them. Just once, I'd like to see a Sunday crossword dedicated to left-handers, with all the clues down the right!
La, la, la - la - la - la....