Clips have a Game ID because they are associated with the game being played at the point in time that they are created. Videos don’t return games, at least not currently, because a Video can be associated with a range of games throughout the duration of a broadcast, so if they do something similar to what Kraken does it would only return 1 game, which may not even be the main one played for that stream, and if they returned an array it would be a change of schema for both the existing endpoint and compared to what people expect based on Kraken.
If you have need for games to be returned, you should check out the Uservoice https://twitch.uservoice.com/forums/310213-developers and vote for the idea.