Meritphase Six Sigma green certification will always help you provided you wish to practice it honestly. My advice has always been that apart from the certification, working knowledge i.e. practical hands on experience is equally important. Do not stop at the certification only, read a lot of books and apply the tools in your work area. Do not take this as just one off certification, try to become a problem solver. LSS is for process improvement but try to be a master in business excellence. BE is far ahead of LSS but Six Sigma green belt is always the first step.
If the same people who discourage you from taking this certification had only known that this knowledge gives you the power to become a problem solver in any field of business, would they have the same opinion? Please tell me one person who is not looking for problem solvers. At every stage in one's life, there are innumerable problems, some people succumb to them and some overcome, where would you like to be? Given a choice, everyone would like to have a person in his team who can they go to to find solutions to the problems at hand.
Please do not get confused, LSS is one sure shot tool by which you may learn to become expert in solving problems, do not talk to people who say otherwise.
Hope this helps. Thanks again