Given our uncertainty about the true model of the economy, knowing that systematic policy in the form of a Taylor-like rule delivers good outcomes in a variety of models means that simple, robust rules can provide useful guidance for policy. Given model uncertainty and data measurement problems, there are, of course, limitations to the use of a simple rule.
The rule is basically intended to work well on average, but central banks look at many variables in determining policy. There inevitably will be times when economic developments fall outside the scope of our models and warrant unusual monetary policy action.