It depends.
If you are an absolute beginner, then I would suggest that you stick with The Hindu. This is because reading a paper develops your language, reading the editorial develops your skill at essay writing and in general you develop background knowledge on most of the things that goes on around you.
However, if you have been preparing for more than a year and has been a regular newspaper reader all through, then it would not do much harm if you were to skip The Hindu and rely on Insights. Again, this should be supplemented with a lot of answer writing practice or you would find yourself in want of words while attempting it during the exam. Newspaper reading actually develops your language without you even knowing it, which can be a humungous boost. The ability to say something in one word or so many words is a key differentiator in good answers.
Finally, I would like to add one more point. As an aspiring civil servant, you should not see the Civil Service Exam as an end but means to an end. The end is being a good servant to the society and to be that, you need to be well aware about things happening all around you. It is near impossible to do that without forming a habit of reading newspaper daily. So, I still suggest you stick to the The Hindu instead of Insights.