Planets and signs do not mean the same thing at all.
Basically Mercury conjunct moon gives a more mental quality to your feelings, and a more emotional quality to your thinking and communicating, because these two planets impart one another's qualities to each other.
Leo is the fixed fire sign. Unless other chart factors discourage it, you probably like to feel (moon) enthusiastic (fire) about your ideas, and may be a persuasive speaker (Mercury.)
My moon is in Leo. On a good day, Leo moons are generous and fun-loving. Because Leo is a fixed sign, we are also very loyal.
With these planets in your 10th house, your career and public image are important to you. A happy fulfilled Leo moon will take on leadership positions.
But as always, we would need to see the entire chart. Something like a square or opposition from Saturn or Pluto would modify the meaning.