How the "Time spent using app" is calculated in the apps review section?

[MegaProfitApps]

I see a lot of applications with 5-star reviews, but then under the review, I see "Time spent using app: 2 minutes".

How a merchant can install a complicated app, use it for 2 minutes and leave a 5-star review?

What am I missing here?
How this "time" is calculated?
Can someone shed some light on this feature please?

Thanks 🙂