For all my blathering, I seldom call to do anything. If D* would allow for cancelling all packages and premiums online, I doubt I would call them at all.
In my time with Dish, I only called/chatted (chat most often) to get some deal that I read about. All other interactions were me and my handy browser.
With D*, you have to call to cancel the premiums or downgrade a package. I find that irritating as hell, so when I call to do that, I also look for a deal. If I could cancel/change without the call, I wouldn't do that. I figure if they are going to make me call and sit on hold for a bit, I want to be paid for my time!!