A nuke hitting somewhere in your country at more-or-less random is still a nuke hitting your country.
Sure, you might luck out and have it land somewhere completely uninhabited. But then again, you might not. And you still have radiation and fallout issues.
Not to mention the whole 'now we either MUST nuke them back, potentially kicking off a war with China, or admit that deterrence is a huge bluff, and watch everybody rush the tech tree to nukes.'