Redundant cards in the pre-constructed Challenge Decks?

[EndersGame]

A question about the Challenge Decks: were they designed to be played against regular decks, rather than against each other?  It seems that they contain several cards (eg some of the environment cards like "Twilight" and "Gates of Morning") which don't really function much when playing against other Challenge Decks, although I gather that these kinds of cards are very important in normal games.  When just limiting games to the pre-constructed Challenge Decks though, some cards like this in the decks appear nearly redundant - either that or I'm not knowledgeable enough about the game yet! (very possible!)  I'm sure that others have thought about this, because I gather that there have been Challenge Deck tournaments and this problem (if it is one) must have surfaced there, so I figured I'd ask about it here.  Are there cards in the Challenge Decks that are essentially useless "space-fillers" when playing only against other Challenge Decks?

[Zarathustra]

They're mostly meant to be played against one another, but they are also intended for general play.  Those environment cards you bring up are useful vs. the other challenge decks, as cancelers of hazards.  Some of the decks rely on doors of night, for example, and so if you have GoM or Twilight, you can save yourself some pain.

[EndersGame]

Perhaps it's because I'm only playing with the five Hero decks, and the environment cards like Doors of Night play a greater role in the five Minion decks?

[Gwaihir]

Are there cards in the Challenge Decks that are essentially useless "space-fillers" when playing only against other Challenge Decks?

I don't think so.

Perhaps it's because I'm only playing with the five Hero decks, and the environment cards like Doors of Night play a greater role in the five Minion decks?

Environment cards play a large role in Saruman and Alatar's decks (too).

[Sly Southerner]

I think the sideboards are pretty much redundant in these decks though.