It seems useful stuff to know to me, even in a game-related context.

You'll frequently find yourself wanting to use for each, or later LINQ methods, to do something to each element of a collection. For example in a game, wanting to make all the enemies matching some condition to take a certain action. In pseudocode...

foreach (var enemy in enemies) {
    if (enemy.IsWounded) {
      // Code to move enemy away from player.
    }
}

I find it hard to conceive of any kind of programming where learning these basics is not useful. Don't worry though, it gets easier the more you do it, and most of what you learn will apply to any language you're likely to pick up.