Draw at random just six people from a population of millions. Take the min and max wealth of those six people. That procedure produces a confidence interval tha

Draw at random just six people from a population of millions. Take the min and max wealth of those six people. That procedure produces a confidence interval that contains the true median wealth of the population more than 95% of the time. Even if the population wealth variance is high. How did I just produce a reliable estimate using a sample size of only six? By quantifying the uncertainty of the estimate. There's a trade off between sample size and uncertainty, and that trade off allows small sample sizes to be useful for many practical applications, most of which can accommodate uncertainty. Again, small samples are informative. Whether they are informative enough for a particular application doesn't determine whether they are informative enough for all applications in general. I certainly wouldn't call them "useless in practice."