Every four years, the Electoral College pushes campaigns and political parties to "expand the map," to reach out and build a broader coalition. This is good for both our diversity and our unity as a nation.
The constitutional, state-by-state presidential election process keeps elections decentralized. That means Presidents have less power over presidential elections, and also less credibility to claim they personify the popular will.
The Constitution is full of checks and balances, each designed to protect liberty and stability in our political system. The Electoral College is a part of this structure, as Trent England explains.