Music in games has to fit the situation. As you can see in these videos, in these particular cases, songs fit. So yes, I can imagine that there are 1 or 2 situations in the game where a song would be nice.
But in most of the game, I think songs with vocals/lyrics would be too distracting. Please keep in mind that the idea is to have a fair amount of voice overs in the game (though full voice overs is probably unachievable, due to the size of the game). To have someone singing songs in the background while you're trying to listen to the voice overs, would get irritating quite fast.
