I think there is a bit of a misunderstanding.
You don't just build it up and knock it down, you develop communities and towns either in Creative (everything is given to you) or in Survival (you gather resources, such as wood to build a pick to collect stone which you upgrade with and then use to mine and build with other materials)
It is certainly a lot more creative than a lot of other games, in others the main objective is normally just to shoot and pass through the levels but with Minecraft it is a lot more social, it encourages team work etc and you simply grow your town/city/kingdom/world together.