If someone had fun, how could this time be wasted?
It's interesting, that the kind of people, that see this as wasted time,
because they think this isn't changing the world, that it isn't ethical
to use your own time this way, that these people will always criticize
themself and others regardless what they do, because there's always
something more meaningful to do.
At the end these people won't change anything in the world, but just
bring harm to themself and others.
In some ways it's equivalent to solving any other seemingly esoteric theoretical problem that people seem to like solving (and some people get PhDs for doing so!). He took a formal system (a particular simplified model of city simulation), and produced a constructive proof of some properties of the system. Of course, the SimCity simulation parameters are unrealistic in a lot of ways, but it doesn't seem inherently any more absurd than the people who get PhDs for game-theory theses that also rely on absurd parameters in their problem setup.
It's interesting, that the kind of people, that see this as wasted time, because they think this isn't changing the world, that it isn't ethical to use your own time this way, that these people will always criticize themself and others regardless what they do, because there's always something more meaningful to do.
At the end these people won't change anything in the world, but just bring harm to themself and others.