Pure popular vote = only large population centers matter because most of the people live there, meaning politicians can safely ignore rural areas that provide all of the food to the cities because they don’t matter votes-wise. Terrible idea for a large country that doesn’t (net) import its food. This also ignores the fact that stupid, easily manipulated people are also allowed to vote.
Electoral college = rural areas have a disproportionately large voice as they should, but large cities are now neglected. Rural votes are also easily influenced by bad actors, like how China is trying to buy African votes to have a bigger say in the UN.