Defence is useless
I feel like def in this game is completely useless. This is only attacking game and whoever got attacked is loser.
With full def build you cant hope to even compare to attackers. On average you will get 7 to 10 times more troop loses than attacker.
So since def is completely useless, infirmaries are useful ONLY if your goal is to raise Profile statistic: "Warriors healed in Infirmary". So in short words, infirmaries are useless too. So since def is useless, you do not need to build any def units, that means you wont have any off units, and no units at all. Since you got no units, you can play paying for protection and grow resources. But there is no fun with resources so you stop playing.
Now since def is completely useless, and def is army, and army is most important aspect of game, you may want to stop playing right now and save yourself money and time on reviving/healing. Healing is useless. Reviving will make you more egoistic bastard bc you spend rl money people kill each other all around the world. So now this is one big rant. Def is useless. Why I wont stop playing right now? Well Im one of those players who like to raise Profile statistic: "Warriors healed in Infirmary".