Santiago is, for sure, worth spending a day in if you are passing through. Walking through the trees and swimming pools up on top of the Parque Metropolitano right in the centre of the city had incredible views and avoids some of the tourist scrums elsewhere. And the General Cemetery (Cementerio General) within Santiago’s centre of the city felt genuinely unique.
But, and maybe a bit controversial, I don’t see Santiago as a highlight of Chile and wouldn’t recommend going out of your way to see it.