Making it an exclusive and then selling it online later, whats the point.
I mean its cool that I can get one now, but why even fucking bother with Comic Con.
AFAIK, they're making it as a limited-edition item, specifically made for sale at Comic Con (and another brony convention). It's "convention exclusive" because it's not going to be mass produced or shipped to retail.
It's production run will have been limited to as many of them as Hasbro guessed they can sell at the convention. And they hope, but can't remotely guarantee, not to be sold out until the very end of the convention.
The leftovers will be given to Hasbro's online shop for clearance, assuming there are any leftovers. If bronies storm Comic Con and Hasbro is unprepared for their numbers, there simply won't be any left for sale online. It's possible for someone to go to Comic Con and still miss out. And there are even non-fans who try to pay for their convention trips by picking up as many popular limited-edition items as they can (regardless of the product, just as long as they think there's money in it relative to size), and trying to resell them for profit on eBay. If Hasbro overestimates Derpy's sales potential at a nerd convention, Hasbro's online shop will have a lot of leftovers.
The Derpy for sale from Taobao is (presumably) an unauthorized additional print run, made by the factory Hasbro trusted to make this "limited edition" item. It's like a perfect copy, without any loss of quality. It's only drawback is that it's unauthorized, and Hasbro isn't getting any of your money, and the factory workers are probably getting more.
