One of the things I like to do when it comes to 
I have almost all of the backgrounds available in the game right now, except for Lake. Unfortunately, I can't utilize all of the backgrounds unless I have multiple cities. Maintaining several cities is not easy unless they serve as specific purposes. For example, many of the top players have more than one tech or background farms.
Of course, the moment when I thought I have almost everything, I noticed that there's a new rare background. I don't know when volcano came into the game, but I likely won't get it from a drop any time soon. So, private trades it is.
But wait, there's more! If you thought backgrounds were the only things you could get, you are mistaken. Animations for the backgrounds exist and they aren't well documented. If you want that extra flare for your city, go for it. It's cosmetics, but vanity items sell.
I do want to point out that animations don't appear on 
In terms of roleplaying
Back to the original point, how does one fit backgrounds into a narrative? I haven't thought too deep about it. Sometimes, it's not worth the effort to explain everything that happens in a game. I mean, most people don't try to make sense of the hyperspace arsenal trope in any game.
One of the ideas I had was the backgrounds represent the diverse geographic regions. Some of you may remember the map I made for the dCity players in the Man Cave. It wouldn't be far-fetched for my own "island duchy" to have diverse settlements. Sometimes, the backgrounds may provide basis for interesting make belief stories.
Anyways, I digress.