There are undoubtedly good reasons to adopt such an approach. The high goal that the team cannot easily achieve motivates them to raise difficult questions, challenge the status quo, and find creative solutions. Trying to achieve such goals broadens the team's understanding of what's possible, and what's not.
This type of goal is also called the "stretch" goal. And it's also a good analogy with stretching in gymnastics. It feels uncomfortable at first, you know that you can barely reach slightly below your knees, let alone the floor. Nevertheless, you keep trying, and over time, you're able to reach lower and lower, until you finally reach the floor. Ambitious goals are designed to work in the same way.