Google opinion rewards is beneficial in its early stage. It gives handsome amount of surveys and gave us opportunity to earn it is some points. However, at present, it is not worth to keep install in the device. It gives hardly 2-3 very short surveys every month where you can earn nearly 3 to 10 INR per survey. Moreover, the survey contains questions mainly rellated to their brand advertisement or their products.
In a nutshell, it is not worth to spend time on the app.