Are PhDs in Engineering worth it for working in the labour market?
This heavily depends on your local circumstances. Nobody can answer this for you - you must find out for yourself.

Go to your local jobs portal (Google for one if you don't know what they are) and search for jobs requiring a degree in engineering. Then repeat the search for jobs requiring a Masters in engineering, and jobs requiring a PhD in engineering. Which jobs do you find the most attractive? How much is their estimated pay? How much would that premium be worth over the course of your estimated working life? How much time &amp; money would have to put to acquire that premium?

Once you have the answers to these questions, you can move on to the big one: is it worth it?