Indeed, a TFSA is used for many different reasons, and it was designed to be as flexible as it is to allow for these different motives. For instance, the fact that you can actually withdraw money and re-contribute what you withdrew is an important feature.
Unfortunately, we don't have details on savings motives.... It would require some form of survey to answer that question, because we don't have that information. We don't collect that type of information. But clearly it's a vehicle or a tool that allows that.