OK, you have the basic game and want to expand your number of x wings. You buy one expansion, get a lovely model and some cool new cards and pilots. You buy another expansion, get another sweet model and,...all the same cards you got last time. As most of the pilots are unique you now have a load of duplicate cards you don't need and can't use. If you want a TIE swarm that's gonna be even worse. It should be possible to buy miniatures without the cards.
Well lucky you cause about every other players would like the option to buy card only without having to buy multiple of the same ship. I suggest you sell your cards on ebay if you have no need for them.
But quite frankly, if FFG were to sell ship without cards, you would save what? 50 cents maybe? So why go to the trouble of making an whole new package just for a couple cents.