Bundles certainly make a great launchpad for some indie developers. I know I wouldn't have been exposed to some fantastic, but obscure, title if it weren't bundled in a pack I bought.
It's tough to say but I read up on Desura's issues with Humble Indie Bundle and why they opted out and eventually struck up Indie Royale. I agree with Desura from a business standpoint but at the same time they cannot neglect that the Humble Bundle is (was?) first and foremost a charity event. People donate (to charities and developers alike) and as a good gesture they get some great indie games in return (that they would likely have never bought otherwise). In most cases I had the games but I donated anyway, I don't need the games, they're a bonus as far as I'm concerned.
From a business standpoint these charity events are not for profit, they're for exposure. A corporation doesn't support a charity for profit it's for Corporate Social Responsibility programs, good publicity, or a genuine concern (as rare as that would seem).