MSI Magus, you're partially correct in most people probably wanting this for a collector's item (either to keep for themselves or to resell). I wouldn't agree so much about the Zelda DS' though. They may sell for $150 or so for the DS only, but new in package they're inching towards (or often over) the $200 mark which is a good $50-$70 over the original MSRP. Around Christmas these will easily sell for $150-$160 I'm sure since it includes New Super Mario Bros, so there is still profit to be had. Maybe not a whole lot, but still some. In the economy we have these days every bit counts.
Oh and it's nice to get it tax free (for those in states Amazon doesn't tax), get $15 off MSRP, free shipping and contribute to CAG/CheapyD. So it's win-win the way I see it.