For example, in world vs world in Guild Wars 2, enemies drop bags that you have to manually collect. Then you have to manually open the bag which may contain other bags that you have to open.
In Clash of Clans, you have to click on the gold mines to collect the gold. This same principle is in Farmville also.
Why don't these games put the loot directly into your bags or gold storage?
Are the players unlikely to notice that they are getting bags or gold unless they take a physical action?
Is there a behavioral reinforcing that's happening by requiring a physical gesture?
This irritates me but when I see it in multiple games it makes me wonder if there is a gaming concept behind it that is fun for some people (or if not fun, part of the "addictive" nature of the game).