Dictatorships allow a state to take a unified direction in policy since the commands all come from a single point; but this silences dissenting voices and removes power from others. In most cases, dictatorships involve repressive and brutal regimes who use their power to oppress the people.
In the past, dictatorships were occasionally beneficial. In Roman times, a dictator would take over the state during a time of crisis, such as invasion or war. The dictator exerted total control, removed the inefficiencies that came with traditional forms of government and relinquished control once the crisis was over. Most dictatorships in history, however, have not been beneficial to those living under government control.