Some people respond more than others. I personally don't care about "achievements" in games at all, despite playing quite a lot of them. However, several of my friends play for achievements often, or alter their behavior so that they get more achievements while playing.

I like the point you bring up. That badges and such make gaming seem less of a wasted time. I know people who can't tolerate open ended games for this reason: no clear goals. Minecraft added The End dimension specifically because of people like this, so that they can "finish" the game.

It has links to status as well I think. Even the name achievements and badges reflect this, and also they're often featured on the profile of the player, so that people can quickly compare others and themselves.