Business users looooove drag and drop. I've seen products burn a stupid amount of money to have it, and decision-makers insisting it was a must-have no matter the cost in time and ongoing overhead in time & bugs for everydamnthing else added to the UI after. I've seen business-side people favor terrible products because they have drag-n-drop, while a better alternative doesn't. They love it.
It's heavy-weight, fragile, lots of implementations are framework-specific, and most of them are horribly buggy, but it's nonetheless a must-have feature in many cases. It'd be a great candidate for better support in the browser, generally, if we're going to insist on using it as an application platform.