I got similar results. I took some sample code from the Apple SpriteKit documentation:

  CGFloat distance = sqrtf((clickPoint.x-charPos.x)*(clickPoint.x-charPos.x)+
                             (clickPoint.y-charPos.y)*(clickPoint.y-charPos.y));

And got this in Swift:

  var distance:CGFloat  = sqrtf((*((clickPoint.y-charPos.y)*()

Most of the code I put in converted to Swift correctly (though it wasn't efficient Swift code) but the above line was just plain wrong. So, it still seems a little buggy but it is a good idea. Like you pointed out, it is only useful for Objective-C to Swift since the Foundation framework is not available in Android.