It's more important as a mental exercise than as absolute advice. Some people put it another way: is your product a vitamin or a painkiller?
For a business to become successful, the product will need to become a must have at some point. If it's not right now, then you need to keep pursuing it until it is.
I couldn't disagree more. When you start using Facebook, it becomes a must have. When I went about deleting all my online accounts, it was one of the two I didn't get rid of. If I got rid of that, I'd lose the most valuable communications medium I've got.
For a business to become successful, the product will need to become a must have at some point. If it's not right now, then you need to keep pursuing it until it is.