Short Answer: Maybe
One thing about National Scholarships is that there will always be multiple applicants, but there will also usually be a limited number because people are discouraged just as you are and don't want to waste their time. It comes down to whether or not you have financial need. If you do not (your parents make >$100K/you have money) then they will always choose a qualified candidate who has financial need. If you do have a financial need then it is definitely worth your time. I have a lot of friends who were able to get smaller national scholarships to help pay for school because there are so many scholarships out there and some will get overlooked by a majority of applicants making them easier to win. Just think of it as a numbers game, yours chances get better with each one you apply for!
And be sure to focus on local scholarships as they are your best chances. Plus, the largest scholarships come from your school, so be sure to apply to multiple places and see what each school is offering to get you to go there.