They're saying it's not collectible. But it is randomized? Why not one full deck? They figure they'll sell more? I just can't see how it's not at least as collectible as "garbage pail kids" ... so even if theirs no competitive angle it's still a cheap trick. I want some.
(Sorry to condense your post unan)
From what we know so far about the cards, they are definitely collectible. But they are not collectible in the same sense as other CCGs (Collectible Card Games).
As several folks keep trying to point out, the GW cards are an optional expansion to the game. In Magic, you have to collect a decent amount of cards before you can build a competive deck, even in casual play (unless you purchase a pre-constructed deck, but part of the fun of Magic is creating your own deck). In Gamma World, if you want to add more zany mutations and tech to your game, they're there. But if you don't, the game plays just fine without any boosters.
In Magic, you've probably got to purchase 6 - 10 boosters at least to start building your own decks. Or get some sort of boxed set, like the new "Deckbuilder's Kit" or a "Fat Pack". And even then you'd still probably want more boosters to be able to build and play a well-constructed, fine-tuned deck. With Gamma World, you can purchase however many boosters as you want, and you're ability to play the game is unchanged. You can buy a case of boosters to try and get the whole set, or you can buy 1 booster and call it good.
Could WotC have used a similar mechanic, drawing random cards from a deck for powers and gear, but used a different packaging scheme? Sure, they could have released a non-random "Expansion Deck 1" (and so on), or experimented with some other scheme.
So, why random boosters rather than an "expansion deck"? If you have just purchased the Gamma World RPG, and you're curious about getting more cards to expand your game, a single booster (and it looks like they'll be 8-card boosters) will likely only run you $2-$3. An easy purchase to make (and an easy sale for WotC). An "expansion deck" on the other hand, would run at least $10, probably more . . . a 65-card Magic decks run $13 (40 card deck plus one 15-card booster).
Of course, if you want to easily collect all the cards, a deck or expansion box would get you all the cards in one fell swoop . . . but for a non-randomized model would likely end up costing more per card.
Also keep in mind that the complete card set is likely to be much smaller than a CCG card set, so if you must collect them all you'll probably drop less cash to do it than you would with the latest Magic expansion.