Azure, rusty, and other super dragons: do they live up to the hype?

Esteemed professionals! Is there any point in preferring Azure, Celestial, and other Greater Dragons to a regular level 7 unit from a castle? To a powerful stack of level 5-6 units? To powerful ranged units? In my opinion, Greater Dragons somehow justify their exorbitant price and resource cost with their health, but not with their damage, and the abilities of regular level 7 units are more impressive. For example, 5 Gold Dragons cost as much as 1 Crystal Dragon, but they deal almost twice as much damage. As a result, you get mega-gnomes, an unkillable mass of units with no offensive power. I personally lost a couple of maps to the computer because I bet on "supermen" instead of regular units from the castle. And it's much harder to control their dwellings. I would like to hear the opinion of experienced players: are there any cases in which you prefer Greater Dragons to regular stacks? How can they be used tactically? Which units are best for capturing and recapturing dwellings, and how? I would be glad to hear any comments regarding Greater Dragons.