There have to be rules or warfare will not be socially constructive. Beowulf is well-mannered and only goes to battle with someone's permission or if one of his band is attacked. He plays by the rules. Got to have rules. It is expected that the guy up top his wealth around focusing on the brave and loyal.
Dragons prevent the dissemination of wealth.
A few well placed dragons and Geatland would come to a stop. Dragons could be seen as bad, but deadly and accomplished warrior-leaders. Dragons and Grendels could be seen as holding some virtues. They are deadly, unflinching and persistent. Jewelry is the quid pro quo for the system when it works.