The Bigger the Dragon, the Better the Treasure
But sometimes the dragon is invisible

Smaug. Grendel. Bahamut. Leviathan. Basilisk.
Dragons guard treasure and cause terror and havoc in the old stories; and they notice if you steal literally anything from their hoard, no matter how small.
Do the dragons enjoy their treasure? They’re not using it or spending it. They’re in the dark…