Google Play star rating doesn't help much to gauge the popularity of apps. It also doesn't help to inform users about how responsive the developers are to users' feedback. What the star rating does is to average off the rating of earlier versions down to the latest ones.Hence, if the earlier versions were good and millions voted for 5 stars, that rating stays throughout. Even when the app failed later that resulted in millions who removed the apps, the star rating would still contain the previous votes. If that is the case, it will not tell new users how good the app currently is. To me, when the star rating is not real-time it does not help. That is because it won't help users to gauge the real-time performance/popularity of the app in question.
Another benchmark about app performance (or popularity) is the number of downloads. Most hot apps would have millions "downloaded". However, this benchmark is also not useful for the same reason as the star rating, i.e. it is not real-time. Assume that initial release of the apps attracted millions to download it. The millions love it, but then due to complacency on the developers' part, the app lost its luster and millions removed the apps from their phones. Such movement is not reflected on the scale. To me, that is not informative. For all I know, the 10 millions downloaded could well be "1000 still using it" scenario.
All-in-all, these two ratings are not being helpful to both users and developers. If these ratings or benchmarks can be made into real-time, it would help users to decide if they want to waste their phone memory downloading the apps. Also, real-time rating will pressurize developers into addressing users' feedback in order to keep their rating high because they can't afford to have the rating drop overnight!
Wouldn't that be a good idea, Google?