Sure, you don't get them until late in the game and all the other infantry the Moors can field are mediocre, but their baseline stats of 16 attack and 22 defense, low upkeep and good morale and stamina more than make up for it.
They're also incredibly vulnerable to a direct cavalry charge. They're eventually countered by crossbows and gunpowder. These powerhouse infantry units have insane defensive bonuses and are very effective in close combat.