This is Zach himself running the Kickstarter campaign (at least as far as I can tell). This isn't a stealth marketing campaign by a Hollywood distribution company, using Zach Braff as the front man. This is Zach the person. He may be a celebrity, and he may have tens of millions in the bank -- but if there's an interesting way to validate demand for his movie, market the movie,
and partially finance it, why shouldn't he try? It's smart business.
Now, I understand the argument that the Zach Braffs and Rob Thomases of the world pose a danger to the future of truly independent artists and filmmakers. As I see it, there are two potential dangers here: 1) that they raise the creative and marketing bars beyond the level of the average Kickstarter artisan's ability to compete; 2) that they attract big companies, who will start subverting the Kickstarter spirit by using it to market, pre-sell, and finance Hollywood productions.
Of these two dangers, #1 hasn't seemed to materialize just yet (though the jury's still out). If anything, the presence of big names on Kickstarter seems to be shining more of a spotlight on the site -- and the rising tide may lift all boats. Danger #2, however, remains distant but possible. One can only hope that the market is smart enough to reward the deserving and punish/withhold from the undeserving. But we'll see.
In the meantime, I see no reason to limit Kickstarter to projects and people "who can't get funding elsewhere." Kickstarter should be a free marketplace for ideas. The quality of the ideas should drive the level of funding the ideas receive. If established filmmakers and stars want to trade off of their brands to get a leg up, so be it -- it seems to provide real value to their fans. Remember that there are real people in the "crowd" behind crowdfunding. If thousands of real people want to pay real money to see X product brought to life, why should we stop them?
If anything, Kickstarter may provide a real alternative to Hollywood financing for creatives who don't want to play the Hollywood game if they can help it. Aren't we supposedly rooting for that?