It is not possible to win Wars and Challenges by attacking

The Power Point system works against you, and strong Castle Walls add to the confusion
You are also forgetting the Victory Tax where we can lose up to 10% extra units every time we win a battle

If one of your dragons die you give 42 power points to your opponents

If you kill one Griifin you only get 15 power points

so you need to kill 3 griffins for every dragon that you lose

Most leagues have learned to ignore Wars and Challenges, and only set up fakes to get the achievements

p,s, Mine's a Guinness, thanks :)

And you receive a fifth of the total power points of units that you lose as PvP points, so massive losses mean a great deal more tournie points. I've never bothered to check if it's a straight conversion in competitions, though.

...Which, now that I consider it more, is fairly fair. Your troops getting wiped out is highly damaging, takes a long time to recoup and the rewards you earn in the tournaments will never come close to making up the difference. The opponent that suffers less loss and earns less points is still ahead of the game.

...This is the most I've edited a post, but my thoughts are refusing to occur in a timely manner. I don't mean "fair" in that it actually balances out and makes recovery attainable, but in the sense that it's a bit of a consolation prize. Still a, "Game over, man! GAME OVER. What the **** are we gonna do now?!" situation, having a huge chunk of your army die.

...Further unnecessary clarification. You win a battle while "losing" in the points department, you live to fight another day, potentially earn more points, and your enemy is smacked flat at a standstill indefinitely.