The data mentioned in the website is based on mathematical models of physical events. Too many times in our science classes, the science investigations are ended when the data table and graph are completed. Little emphasis is placed on students looking for patterns and relationships, or discovering mathematical models of the phenomena being studied. But there are times when the students cannot collect the data, but they can still manipulate it, look for patterns, and develop mathematical models of the event. That is the purpose of using a REAL data set generated from mathematical models, which have been derived from REAL data.
Scientists use computer models to predict where hurricanes are going to strike.
Physicists use models also as well as astronomers. If scientists use computer generated data and models to engage in scientific inquiry, then students should also in the classroom. The nature of science includes looking for patterns and relationships. This can be done with investigating mathematical models of phenomena being studied.