The point is both to have fun with this kind of simulations, and also explore the "functional core / imperative shell" approach to architecture. I also developed a tile and tile effect definition DSL, which makes this even easier to extend. From this point of view it's a success: easy testing, easy extension,
Gameplay-wise the simulation is too simplistic, and needs input from people interested in this kind of toys. The original Micropolis/SimSity is the last time I built a virtual city.