Can't say for sure because the ones I watch usually test whether or not something is too close to a wall to be used or if sims can walk around certain objects.
A lot of people have more fun building rather than playing, and that's okay. TS4 has been focusing heavily on build mode for the last few years because that's where it's strongest. It's become a building simulator to a lot of people rather than a life simulator.
That said, player builds can be used as a sort of base for you to change up to fit your playstyle or needs. Some people do just create nice builds without thinking about functionality. I think that's okay.
I'm not a builder btw, I'm absolute garbo at it :p
