If you want a job at a PSU, writing CLAT is essential as they look at your CLAT PG rank. Also, they may pay higher salaries to LLM candidates. You can also apply as a fresher in many law based agencies to gain experience.

LLM is necessary for joining the academia, and can be useful in research institutes, thinktanks and NGOs working on policy issues as well. Considering that a large number of law schools in India now pay quite well, this is significant. Similarly, requirement of lawyers are thinktanks, NGOs and research bodies have drastically increased over the last few years. These are great career opportunities.

Hope this helps
All the best