Hello,
Six Sigma Black Belt can be very useful to anyone, but especially to someone who can cope with and enjoys the rigors of serious statistics, such as Design of Experiments and Probability. Generally, math and statistics are not the strong points of individuals who opt for an HR stream. So, before you enroll in the course, review the course material to see if you would be able to keep up with it. Having taught the course, I know that individuals from an engineering background are most successful at it. Therefore, review your performance in math from your school or college before making a decision.
On the other hand, you may consider taking the Green Belt course, which can help you as a manager in your field.
Best of luck,
Anupam