Hmm... I'm not sure how to explain because it sounds really obvious, and its hard to do so without repeating myself.

Unit's stats VS enemies - as it says, it's the UNIT'S stats. It means that it affects you. Higher miss multiplier means YOU will miss more (bad for you). Higher crit multiplier also means that YOU will crit more.

Enemy's stats VS this unit - This affects the enemy in front of you. Higher miss chance here means that the ENEMY will miss more often against this unit, which is good for you. Every time it attacks, it has its chance to miss multiplied by a certain number. In other words, it can make you harder or easier to hit/crit.

Once again: Unit's stats is exactly what it says, unit's stats. It makes your unit hit more, or crit more. It basically affects the unit's offensive capabilities. On the other hand, enemy's stats, like it says, affects enemies. So setting enemy's crit to 0 means that any enemy who attacks your unit will never crit. Basically, defensive.

Think of unit's stats as "what you see", and enemy's stats as "what enemy sees".

If you have any more trouble, hover your mouse over the sliders. I think I left descriptions there to help you sort it out.

that actually makes a lot of sense, thank you