I agree that that is one of the functions of the electoral college, but not the only one, at least at the start of the country. The 3/5ths compromise was put forward to address concerns of the southern colonies that they would be dominated by non-slave states because they would only count votes of white males, making their population much smaller than it actually was. For non-American readers, the 3/5ths compromise was an agreement to count slaves as 3/5ths of a person. Of course slaves still could not vote, so 3/5ths of nothing is still nothing. To go along with the 3/5ths arrangement, some mechanism had to be invented to turn that 3/5ths into presidential votes. The electoral college filled that role. Each state would be allocated some number of electoral college votes in proportion to their population, which in the case of slave-holding states was all the non-slave population plus 3/5ths of the total number of adult slaves. The electoral college allowed slave states to derive political power in proportion to the number of slaves, without actually allowing the slaves themselves any power.
So I would say the electoral college had two functions: to keep power in the hands of the wealthy elite, and to allow southern slave owners to profit politically as well as financially from their slaves. Today the system may not favor slave owners, but it ensures that residents of some states have a disproportionally large voice in presidential elections, and other states have their voice diminished. For example, voters in Kansas have 3 electors, or about 1 for every 180,000 people. On the other hand, Texas has 1 elector for every 763,000 people. Are people who happen to live in Kansas really worth 4 times as much as people who happen to live in Texas? Texas has about the same population as Alaska, Colorado, North and South Dakota, Idaho, Oklahoma, Kansas, Nebraska, Nevada, New Mexico, Montana, Wyoming, and Utah combined. Texas has 38 electoral votes, and all those states combined have 63. You could make similar comparisons if you substituted California for Texas. So much for one person/one vote!
The electoral college serves no useful purpose, it was conceived in order to support evil and it is deeply undemocratic. It's past time for it to be abolished.