Both aspects are valid, but I think what you point out is also very important. I know several people who are not launching their product because they are doing yet another iteration of user tests and fine tuning. On the other hand my experience has been that if your product provides anything useful for people, they will be able to extract it. I am often surprised at the complex user interfaces people master - stuff I personally would never have the patience to put up with, but "normal people" somehow master it, even if at the same time they might not be aware what a browser is. (One example: Facebook groups, horrible interface but apparently people use it).