"The significance of a man is not in what he attains, but rather in what he longs to attain." Kahlil Gibran
We constantly measure ourself, and our success, based entirely on our results. Results are what we do and we have a strong belief that what we do is the same as who we are. Results are a combination of things both within and outside of a leader's control.
Results can be observed by others. While these are clearly important, it again reinforces the notion that the significance of a person is measured only by the observable outcomes he or she achieves.
Obviously a focus on success means a crucial attention to results. But a focus on significance brings about something else entirely. What a person longs to attain, their vision of what is possible to accomplish, can be (and should be perhaps) greater than that which is the possible sum of their acts. In other words, if you set your target high enough, you may not attain it, but you may have success beyond what you can imagine.
The point is that it isn't a zero sum game between actions and vision. It is true that your actions will ultimately bring about your results, but what you truly desire to attain will be what drives the commitment to achieve in the first place.