Well, if the angels are built, then our hero moves faster around the map.
He can first eliminate the guards guarding the artifacts, focusing on smaller units, and using wyverns... and do it everywhere without losses, while with cavalry, you might lose a horse or an archer.
This is a tactic for a 2-minute control, but if you're not playing against a newbie and the game lasts 6 minutes, it's just ridiculous. They'll break Utopia while you're running around the map.
