A way of conceding a point, or admitting while you may not agree with someone's opinion, they are entitled to have it.
1. BroA: Dude, why didn't you take that job? The benefits were killer!
BroB: Maybe, but it was so far out, I'd have spent more on gas than what they were willing to pay me.
BroA: Fair enough.
2. American: Personally, I don't like the British, because the British don't like us.
Brit: Fair enough.