According to the Elder Tale Nobility, an 'Order of Knights' is recognized as an official military force. A city that has such a force is considered a military asset, though the Round Table Alliance clearly stated that Akihabara has no such organization. This is not considered by the nobility when they demanded that the Adventurers send out troops to defeat the goblin hordes invading the continent. In Lander society, Knights are the second-lowest noble title a person can have, just above civilian.
The Adventurers' role-playing subclass provides very little combat benefit for those who have it. However, that fact has not decreased its popularity as one of the original and oldest subclasses in the game.