Google opinion rewards app is an survey app provided by the Google India. I installed this App to get rewarded by Google and to use the money for mobile recharge but when I install that app I know that the money is only used in the Google Play Store digital money it is not used for the recharge of mobile or for buy another gift card.
The poll is running by the Google opinion reward app is not so frequent the survey question are comes once or twice in a month and the rewards is all around 8 to 15 rupees.
In My 3 month experience there are only ones survey is related to banks and all others are about Google product like app usage Google product uses etc.
Money rewarded from Google opinion reward is credited to Google Play Store as a gift card money the money is used when I brought an app on Play Store also the money is used to purchase any in app purchase products.
To use this app I got only 2 product in playstore one is Poweramp Pro and another is 80 gems in Clash of Clans game. Total in rupees 140 it means I earn about 140 rupees in 3 months.
If you like to buy an app from Playstore this app is good for you but for me it is useless because generally I used free apps in Play Store.