Is it unethical for Microsoft to "sell" gamer points which are needed to download additional game content that was previously free?

If you play a bunch of Microsoft’s games then you probably have a whole bunch of points to spend on what were previously free upgrades to a product. However if you have no Microsoft points, you can then buy them. So basically, if you want to download content for say Fallout 3, you can either pay with game points (800) or pay $10 for what should be a free upgrade.