I have been using this app for the past three months. Initially I though useless as it gives reward points not real cash. However after a month I realized that the money can be encashed by some apps. Though they give only 60% of the rewards poin and keep 40% with tehmselves.
Considering the fact that google normally offers you survey to the tune of Rs 100-150 a month, it is worth earning Rs 60 to Rs 75 a month without much hessle. I found google survey best among the rest.
You may try convertor to encash the google rewards if you agree to sell it for 60%.