My guess is it's because whereas in the early days they had "strict rules" that only the winner got a contract deal, they've now started dishing them out to anyone who even vaguely looks like they might sell a few records. And that they want to be able to market as many as possible as "X-Factor Finalist xxxxxx" rather than simply "X-Factor contestant who was so bad they couldn't even make the final".
It looks nailed on that OD, Matt & Cher at the very least will all get a contract. Possibly not just them.