If you add the difference in the earnings for a lifetime, it may add up to many lakhs of rupees.
But money is not all. There are other important advantages of success such as better job, pride of achievement, more respect, more self-confidence, more satisfaction, greater security, etc.
This shows that one additional mark in a competition may be worth a lot because it can make the difference between success and failure. And you should do whatever possible to get each additional mark.