I would gently disagree, if he is running a subscription site he needs to get billing working to determine what folks will actually pay for. Having a billing system communicates a serious intent to your prospective customers that you want to provide value and are in it for the long haul.
Good point. My problem is that I find it hard to delegate (or am too stingy to spend money on services). So I've wasted endless hours on fiddling with CSS. Since I'm a very good programmer but a very bad designer, that was probably not efficient. Law of comparative advantage and all that.
OTOH, there's not much need for billing if you don't have something fantastic to sell.
My experience is that when you really focus on the one big thing all the small things get even smaller once you get around to them. Hope that helps.
EDIT: It just occured to me that pg describes this concept (What's the best thing you could be working on, and why aren't you?) much more eloquently here:
http://paulgraham.com/procrastination.html