More than 1 game world save option?

The very first thing I do, whenever I install TS4 on a new device (or on a wiped device ... always fun), is start a new game (+ in top right corner), take whatever sim pops up on the CAS screen (randomize name, just grab a random aspiration and the first three traits my mouse hits), hit the check, and then pop them onto an empty lot. As soon as the lot loads (I keep my finger poised over the pause button), I pause it before the game has a chance to spawn anything (townies, whatever). Hit the 3 dots in the top right corner to manage worlds, and go to Household Management (just to the left of the 3 dots).

Delete my 'dummy sim' household (later, you can also delete them from your library, since any household you create in CAS gets automatically saved to your library when you start the game), then go to "Save As" and save the world as "Empty." This is my jumping off point for every future new game I start, whether I want to create a new household to move in, play a pre-existing family, or just build. I like having this save, because I can go in and, say, add in my updated parks that I've made, or swap out the regular Windenburg gym for the one I updated, and then I only have to do it once, I don't have to keep making the same changes to each new world I start. IMPORTANT TO REMEMBER: if you're going to use your "Empty" world to start new games, be sure that, once you are ready to start a new game, you click "Save As" and save it as a unique game name (even if it's just something as simple as Smith Family 1).

My next step is to go to "Save As" again and save it a second time, this time as "Building." Once I am positive I am in the "Building" save, I go back into Household Management and delete all sim families (except 1, since you do need at least 1 sim, but you can evict them from their home). Then I go through and start bulldozing whatever I'm not interested in keeping.

Then, whenever I come back into the game, I just click on the floppy disk in the top right of the image above, and decide where I'm going: my empty world to tool around a bit (or start a new game), one of my existing families, my building world to tinker about and, well ... build. Etc. I almost never actually click on that little + in the top right corner anymore.