The tactics skill description just says it is for organizing and planning a
military operation (which sounds a lot more involved than just a bit of combat).

Under group initiative, on the other hand, it says that the person with the
highest Tactics skill is the best person to designate to roll for your group.
No mention of why it is better.

The shortly after it does say that he can use his tactics skill to add bonuses.
This is mentioned as an additional use in combat, which implies that there is an
original use. Am I missing something?

Thanks.

-Scott