Built for the people for entertainment. Had gladiator events, hunts, performances, executions, races, naval battles, a consecrated space. Built with arches on top of arches. Engaged columns with all the orders to show the mixture of time and past events. Showing they understand history, etc.
It was built for the people on the site of a former monument for Nero. Nero, the emperor previous, had spent endless time and resources building tributes to his own splendor. But this is was a symbol that this new emperor was a man of the people.