If there is no competition, elections will become pointless.
Regular electoral competition provides incentives to political parties and leaders. They know that ifthey raise issues that people want to be raised, their popularity and chances of victory will increasein the next elections. But if they fail to satisfy the voters with their work they will not be able towin again. Thus it motivate them to do good things.
Political competition enlighten people about election and democratic principles and during their competition people can identify the party that they should choose.