Well, the purpose of such a question is obviously to help them decide which applicant will make the best use of their money.
Part of that will be to convince them that your goals are sympathetic to theirs. If the scholarship is related to the field you are studying in, you don't have to convince them of its
worth, but they would want to know what goals or vision you
have once you have completed your studies.
If it's not
directly related to your field of study, there will be some other interest/bias that they want to support with their funds, and you will need to convince them that you are the applicant who best fits into that picture -- as well as pumping your own goals.
Sell yourself as the candidate who warms the cockles of their special interest and is going to go on to make a difference in her field of study. But do it humbly, or somebody on their committee will say "Who the heck does she think SHE is?" and give it to somebody else.