“potion of liver damage”? So… beer?

Yes, you don’t actually have to switch. You could also throw a coin to decide to stay at the current door or to switch. By throwing a coin, you actually improved your chances of winning the price.

Reddit is not interested in having a “good” app (as viewed from the perspective of the users). Reddit wants an app that collects as much data, and generates as much revenue, as possible. Those goals are sometimes contradictory to what normal users want.