This is called a reward for active courtiers. Basically the region lord encourages courtiers.Managing an estate is the same.Knight manages an estate in the region and region lord pays him.Also region lord can kick out knight as he pleases.The region with everything in it belongs to the region lord.A knight is merely hired help.
No, the knight is in a feudal contract of mutual obligations, though game mechanics aren't perfect in relaying this. It is completely different to the modern concept of paid work. For a courtier part of their obligation can be assumed to be courtier work, the details of which are left to the realm. To pay them a "reward" would be the same as posting some sort of gold pot for the region that warriors would get paid from every time they were part of defensive force in the region.
Also the Lord doesn't PAY anyone. The knight is entitled to the produce and wealth of the estate he holds. This is seen better in the new system where an estate is defined as a abstract percentage of the wealth of the region, which the knight collects and then pays tax on to his Lord as part of his obligation. Money goes UP the chain, Land and the wealth it can produce moves down the chain.