Hello

That entirely depends on your perspective.

You can do MTech through GATE.The advantage is getting a placement in IITS/NITS which accepts GATE scores and you can also do jobs in PSU later on if it interests you.

If the idea of higher studies interest you and you are passionate about technology then definitely go for it. The job prospects in areas other areas like academia, research & development and technical fields are also there.If you are good and technically sound, MTech can open up various opportunities for you.There is a also dearth of talent in research and development industry in the government and private sector.

Thank you!

No it's absolutely not necessary to do mtech after Btech. 

But it's guided that pursuing M. Tech after B. Tech is a very good alternative for you if you want to add value to your education and qualification. This value addition in the profile helps in future. 

Technical skills matter a lot nowadays, you will be exposed to the applications of engineering in day to day life. You will get more insights into the subject, and will land you to a better job. 

Go ahead and follow your dreams