Physics Tutor - currently at IIT, KVPY Scholar, IMO AIR - 2
Seems to be a very generic doubt and I had similar views before coaching.
My answer would be, depends totally on you.
Let me start by describing what you get at a coaching institute - online or offline.
Coaching institutes - online or offline are no way a subsitute for hard work, but they do the job of giving you the right direction for your hard work.
Given the large portion of JEE and the limited time, coaching institutes provide you with the just the right study material, which has the optimum no. and variety of questions from all the necessary topics. Regular tests taken by these institutes prepare you for the exam environment. The responsibility of completing the huge syllabus lies on the shoulders of the institute. Additionally, it is important to have a circle of friends seriously preparing for JEE of similar iinterest and level as yours to discuss doubts and help each other, which we generally find at a good coaching.
In a nutshell, these institutes provide you with the right resources coupled with their experince and guide you in your hard work in a strucutred manner.
If you believe that you can be well disciplined, keep working hard regularly and find all the resources on your own, Self study is not a bad option.