It prevents a regional candidate from controlling the whole country. I candidate can't run up huge totals in New York, New Jersey and New England and still win the presidency.
Quite the opposite is true. Abraham Lincoln wouldn't have had a prayer in the 1860 popular vote. Lincoln was a regional candidate and won only because of the EC.
Lincoln actually had support, and won, across many regions, the Northeast, the Midwest, and the West. Had he just carried New England and the Mid Atlantic states that he carried, the race would have gone to the House.
There's no way anybody could win with just New England and Mid-Atlantic in PV either.
No, and that is my point.
Even in 1860, Lincoln, or any other candidate, had to be more broadly acceptable to the electorate, in order to get a majority of the electoral votes. And
this was probably the most divisive election in US history.
The Electoral College basically forces candidates to have a broad based appeal.