What are the fallacies associated with seeding based purely on KenPom?

I don’t dig too much into metrics besides the box score and team stats after my teams play, so I’m not well versed on how seeding is done and the associated metrics. People reference KenPom all the time, why would it or any other similar metric based performance tracker not be the sole determinant for seeding? AFAIK, KenPom takes opponent strength into consideration, so it feels like it should be an accurate measure of how good a team is.