How does review exchange help?

Consider me a noob. But how does it help?
Since the reviewers are all developers, the chances of getting your app played properly are remote. Ads won’t count for anything. The app will probably be uninstalled quickly.

So how exactly do the reviews without retention help? Does the app rank gets drastically increased by such reviews?

Enlighten me please.

Reviews helps a lot to increase the downloads globally

Reviews let the other know that hows this apps works and its hows contains it quality