ok. If it is scored as a proper MT fight punches score less than kicks and knees hence they're often used to set up other strikes. Throws also score.

With regards to learning both, it's a different thing, you could learn boxing BUT you wouldn't want to duck under a hook because you'll get kneed in the face. If you clinch in boxing you tend to shell up if you do that - knee in the face! When you clinch in MT you straighten up.
So in one class you would be learning to do the exact opposite in the other class. Not saying you can't do both but you learn something well enough if becomes reflexive, don't want to do the wrong thing because your brain has paused